The Anglo-Soviet invasion of Iran, also known as the Anglo-Soviet invasion of Persia or the Allied invasion of Iran, was the joint invasion of the officially neutral Imperial State of Iran by the United Kingdom and the Soviet Union in August 1941, during World War II. Iran would remain under British and Soviet occupation until 1946, months after the war's end. Britain began to withdraw on 2 March 1946, while the Soviets did not leave until May, having sparked an international crisis through their refusal to do so.
The invasion, code named Operation Countenance, was largely unopposed by the numerically and technologically outmatched Iranian forces. The multi-pronged coordinated invasion took place along Iran's borders with the Kingdom of Iraq, Azerbaijan SSR, and Turkmen SSR, with fighting beginning on 25 August and ending on 31 August when the Iranian government, under the rule of Reza Shah Pahlavi, formally agreed to surrender, having already agreed to a ceasefire on 30 August.
The invasion took place two months after the Axis invasion of the Soviet Union and the Soviet Union's subsequent alliance with the United Kingdom. The attack also took place less than two months after Allied victories over pro-Axis forces in neighboring Iraq, French Syria and Lebanon. The invasion's strategic purpose was to ensure the safety of Allied supply lines to the USSR (see the Persian Corridor), secure Iranian oil fields, limit German influence in Iran (due to the presence of Germans in Iran, mainly for industrial purpose) and preempt a possible Axis advance from Turkey through Iran toward the Baku oil fields or British India. Following the invasion, on 16 September 1941 Reza Shah was forced to abdicate and went into exile, being replaced by his young son Mohammad Reza Pahlavi.
Background
In 1921, Reza Khan Pahlavi performed a coup d'état against the Qajar dynasty (1789–1925). He later overthrew the ruling dynasty in 1925 and crowned himself as Reza Shah that same year. He commenced an ambitious program of economic, cultural, and military modernization. Reza Shah's regime established schools, built infrastructure, modernized cities, and expanded transportation networks. The Shah pursued a foreign policy of neutrality, but depended on Western financing in order to finance his ambitious modernization projects.
In early 1940, as Britain was involved in war with Germany in North Africa, it grew concerned about German access to the Persian Gulf, especially in light of Germany's non-aggression pact with the Soviet Union. The British began to accuse Iran of supporting Nazism and of being pro-German. Indeed, Reza Shah had developed great sympathy for the Nazi cause. Although Reza Shah declared neutrality at an early stage of World War II, he clearly tilted towards Germany, and allowed hundreds of German agents to operate inside Iran. Iran assumed great strategic importance to the British government, which feared that the Abadan Refinery (of the UK-owned Anglo-Iranian Oil Company) might fall into German hands. Refining eight million tons of oil in 1940, the refinery made a crucial contribution to the Allied war effort. Relations between Britain and Iran had been strained since 1931 when the Shah unilaterally cancelled the D'Arcy Concession – a 1901 agreement that had given the Anglo-Iranian Oil Company the exclusive right to prospect for Iranian oil for 60 years, with Iran receiving 16 percent of the net profit. Led by the Shah, the Iranian imperial government accused the Company of undercutting its share of the profit by clandestinely reinvesting new capital into subsidiary companies, and thus excluding a significant sum from the annual capital gain calculation. Though the Shah promptly renegotiated a second concession with the Anglo-Iranian Company – with terms that better protected the Iranians' stake – the diplomatic conflict created an impression that the Shah was hostile to British oil interests.
Following Operation Barbarossa, the Axis invasion of the Soviet Union in June 1941, Britain and the Soviet Union became formal allies, providing further impetus for an Allied invasion. In a major strategic analysis in the New York Times on a Sunday following Barbarossa, the famous international correspondent C. L. Sulzberger stated, in reference to the Operation Orient, "It is considered virtually a certainty by military experts that if the Reich succeeds...an attack on Egypt will be launched. Should the Germans...occupy the Caucasus and then push on to Iran and the Persian Gulf they will then outflank the British Middle Eastern positions by a wide sweep and perhaps by Autumn begin to make trouble in Iraq." With the Wehrmacht steadily advancing through the Soviet Union, the Persian Corridor formed by the Trans-Iranian Railway offered one of the easiest ways to supply the Soviets with Lend-Lease goods sent by sea from the then technically neutral United States. British and Soviet planners recognized the importance of that railway and sought to control it. As increasing U-boat attacks and winter ice made convoys to Arkhangelsk (which commenced in August 1941) dangerous, the railway seemed an increasingly attractive strategic route.
The two Allied nations applied pressure on Iran and on the Shah, which led to increased tensions and to anti-British rallies in Tehran. The British described the protests as "pro-German". Iran's strategic location threatened Soviet Caucasian oil and the Soviet armies' rear, and any German advance south-eastwards would threaten British communications between India and the Mediterranean.
In July and August, the Shah refused demands from the British for the expulsion of German residents from Iran (mostly workers and diplomats). A British embassy report, dated 1940, estimated that there were almost 1,000 German nationals in Iran. According to Iran's Ettela'at newspaper, there were 690 German nationals in Iran (out of a total of 4,630 foreigners, including 2,590 British). Joan Beaumont estimates that "probably no more than 3,000 Germans actually lived in Iran, but they were believed to have a disproportionate influence because of their employment in strategic government industries and in Iran's transport and communications network."
However, the Iranians began to reduce their trade with the Germans in the face of Allied demands. Reza Shah sought to remain neutral, not wanting to anger either side. This approach became increasingly difficult in the face of Anglo-Soviet demands. British forces were already present in sizeable numbers in Iraq as a result of the Anglo-Iraqi War of May 1941. Allied leaders feared that the Nazis were planning on using Iran as a platform for attack across the Soviet Union's southern border, adding an extra layer of complication to the Allied war effort. This directly led to the joint Soviet-British invasion.
Invasion
The invasion was a surprise attack described by Allied forces as rapid and conducted with ease. Prior to the invasion, two diplomatic notes were delivered to the Iranian government on 19 July and 17 August, requiring the Iranian government to expel German nationals. The second of the notes was recognised by the prime minister Ali Mansur as a disguised ultimatum. General Archibald Wavell later wrote in his despatch, "it was apparent that the Iranian Government fully expected an early British advance into Khuzestan and that reinforcements, including light and medium tanks, were being sent to Ahvaz".
Following the invasion, Sir Reader Bullard and Andrey Andreyevich Smirnov, the British and Soviet ambassadors to Iran, were summoned. The Shah demanded to know why they were invading his country and why they had not declared war. Both answered that it was because of "German residents" in Iran. When the Shah asked if the Allies would stop their attack if he expelled the Germans, the ambassadors did not answer. The Shah sent a telegram to US President Franklin D. Roosevelt, pleading with him to stop the invasion. As the neutral United States had nothing to do with the attack, Roosevelt was not able to grant the Shah's plea but stated that he believed that the "territorial integrity" of Iran should be respected.
In his post-war memoirs, Winston Churchill invoked the brocard, "Inter arma silent leges" to justify the "exercise of overwhelming force against a weak and ancient state."
Beginning of the invasion
The Royal Navy and Royal Australian Navy attacked from the Persian Gulf, while other British Commonwealth forces came by land and air from Iraq. The Soviet Union invaded from the north, mostly from Transcaucasia, with the 44th and 47th Armies of the Transcaucasian Front (General Dmitry Timofeyevich Kozlov), and the 53rd Army of the Central Asian Military District, occupying Iran's northern provinces. Air force and naval units also participated in the battle. The Soviets used about 1,000 T-26 tanks for their combat operations.
Six days after the invasion and the ensuing Allied occupation of southern Iran, the British divisions previously known as "Iraq Command" (also known as Iraqforce) were renamed "Persia and Iraq Force" (Paiforce), under the command of Lieutenant-General Edward Quinan. Paiforce was made up of 8th and 10th Indian Infantry divisions, 2nd Indian Armoured Brigade, 4th British Cavalry Brigade (later renamed 9th Armoured Brigade), and 21st Indian Infantry Brigade.
In response to the invasion, the Imperial Iranian Army deployed nine infantry divisions, some of them motorised; two of the divisions also had tanks. The Iranian Army had a standing force of 126,000–200,000 men. While Iran had taken numerous steps through the previous decade to strengthen, standardise, and modernise its army, the army did not have enough training, armour, or air power to fight a multi-front war. Reza Shah's modernisations had not been completed by the time war broke out, and the Iranian Army had been more concerned with civilian repression than invasions.
The Iranian army was armed with the vz. 24 rifle, a Czech version of the Mauser Gewehr 98. Iranian troops also had other Czech small arms like the ZB vz. 30 and ZB-53. Iran had bought 100 FT-6 and ČKD TNH light tanks as well as some AH-IV tankettes and additional LaFrance TK-6 armoured cars, enough to outfit their 1st and 2nd Divisions. Further Iranian orders had been delayed by World War II. While it was a large order and they were excellent tanks, they were not enough to defeat a multi-front invasion by two great powers. The changing nature of tank warfare in the 1930s made all but 50 of them obsolete when the invasion began. The Imperial Iranian Air Force (IIAF) at the time flew a motley collection of outdated biplanes, including British Hawker Fury fighters and Hawker Hart bombers, and French aircraft such as the Bréguet 14, Bréguet 19, Potez VIII, and Blériot-SPAD S.42. The IIAF also had some Soviet-made aircraft: copies of the British DH.4 and DH.9A made by the Polikarpov factory, although not modern types such as the original Polikarpov R-5.
The Iranians had little time to organise a defence, as the Allies achieved a tactical surprise. The war began in the early morning of 25 August, when RAF aircraft entered Iranian airspace. They bombed targets in the cities of Tehran and Qazvin and various other towns and dropped leaflets urging the Iranians to surrender. The Soviets bombed targets in cities such as Tabriz, Ardabil and Rasht. Civilian and residential areas were hit, and several hundred people were killed and wounded. Reza Shah refused requests by his generals to destroy the road and transportation networks, largely because he did not want to damage the infrastructure that he had painstakingly built during his reign. That contributed to the speedy victory of the Allies.
With no allies, Iranian resistance was rapidly overwhelmed and neutralised by Soviet and British tanks and infantry. The British and Soviet forces met at Sanandaj (called Senna by the British) (160 kilometres (100 mi) west of Hamadan) and Qazvin (called Kazvin by the British) (160 kilometres (100 mi) west of Tehran and 320 kilometres (200 mi) north-east of Hamadan) on 30 and 31 August respectively. Faced with massive defeats, the Shah ordered his military to stop fighting and stand down on 29 August, four days into the invasion.
British theatre
Invasion of Khuzestan
The British assembled a naval task force under Commodore Cosmo Graham to seize Bandar Shahpur, Abadan, and Khorramshahr. It attacked at dawn on 25 August 1941.
The naval attack began at 04:10 at Abadan when HMS Shoreham opened fire on the Iranian sloop Palang, sinking it in a single salvo. The Abadan refinery was of vital importance to the British commanders as well as keeping the employees of the Anglo-Iranian Oil Company safe from possible reprisals. Khuzestan Province was defended by 27,000 troops from the 1st, 2nd, 6th and 16th infantry divisions, consisting of both light and mechanised infantry. All Iranian tanks were deployed in Khuzestan as part of the 1st and 2nd divisions. Shoreham remained in the area and provided naval gunfire support. The Iranians managed to put up a resistance, and the refinery and the city were captured that afternoon after hand-to-hand combat resulted in the deaths of several British and Indian troops.