The 'Battle of Deir ez-Zor' was part of the Allied 'Exporter' operation to wrest Syria and Lebanon from the Vichy French (3 July 1941).

The 'Battle of Deir ez-Zor' is notable for the bold outflanking tactics employed by Major General W. J. Slim, commander of the Indian 10^th Division of the Iraq Command. The tactics presaged Slim’s employment of similar but larger-scale tactics in 1945 while commanding the British 14^th Army in Burma.

On 8 June, the Allies had launched the 'Exporter' offensive with attacks to the north from the British mandate of Palestine and Trans-Jordan into Lebanon and south-west Syria. The British intent was the prevention of Germany from using Vichy French territory as a springboard for attacks on the Allied stronghold of British-controlled Egypt as the Allies fought a major campaign against Axis forces farther to the west in the North African desert. By 20 June, Damascus had been captured, and the commander of the Allied campaign, General Sir Henry Maitland Wilson, ordered two further attacks from western Iraq toward Palmyra in central Syria and Aleppo in northern Syria.

The force which gathered at Haditha in north-western Iraq comprised Brigadier C. J. Weld’s Indian 21^st Brigade Group and Brigadier R. G. Mountain’s Indian 25^th Brigade Group of Slim’s Indian 10^th Division, supplemented by the 2/8^th Gurkha Rifles of Brigadier D. Powell’s Indian 20^th Brigade Group, which had been detached for a different task. The division was to advance up the Euphrates river in order to take, in succession, Abu Kamal, Deir ez-Zor, Raqqa and Meskene on the river before leaving the line of the river to advance westward to Aleppo in the far north-west of Syria.

Deir ez-Zor was the chief city of eastern Syria, and was significant for the fact that it boasted two bridges across the Euphrates river.

The advance units of the Indian 10^th Division departed Haditha on 27 June and took Abu Kemal without opposition. By 30 June, the division’s main force had been concentrated there and moved out on the following day toward Deir ez-Zor. Progress on the poor road was slow, and in fact made more difficult by air attacks from Vichy French aircraft, but by a time early in afternoon there were units within 9 miles (14.5 km) of Deir ez-Zor.

Slim’s original plan was to attack the town from the south-east while sending a flanking force to pass wide round the south-east before attack along the road to Aleppo in the Vichy French forces' rear. Fuel was running low and the risk of the flanking force running dry and becoming immobile just as it came into contact with the Vichy French was a factor which had to be taken into consideration. Slim decided that the risk was justified by the opportunity it afforded of taking the Vichy French defenders by complete surprise.

The 2/10^th Gurkha Rifles attacked Deir ez-Zor from the south-west at 09.00 on 3 July. The flanking column (comprising infantry of 4/13^th Frontier Force Rifles and armoured cars of the 13^th Duke of Connaught’s Own Lancers) had left Mayadin, farther downstream on the Euphrates river, at 04.15 and crossing the Palmyra road running south-west across its path about 20 miles (32 km) from Deir ez-Zor and reaching the Aleppo road by 10.30. As Slim had hoped, surprise was complete and the flanking force advanced rapidly into Deir ez-Zor, capturing the bridges intact and destabilising the defences facing the Gurkhas advancing from the south-east. By 11.00, these positions were abandoned and the two attacking forces linked in the town. By 15.30, the last opposition in the city had been silenced, although the Vichy French air force continued to deliver effective attacks on the Allied ground forces.

Only 100 prisoners were taken because the bulk of the Vichy French troops, which comprised largely Syrian men, changed into civilian clothes and merged into countryside. However, 50 lorries, nine pieces of artillery and five aircraft were captured, and a considerable haul of weapons, ammunition and petrol was made.

On 5 July, Raqqa was taken without opposition, although the Vichy French continued to hold the upper hand in the air and the Vichy French air force continued to inflict casualties such that supply convoys took to travelling at night. Meanwhile, two brigade groups, each of two infantry battalions, operating independently under the control of the Headquarters British Troops Iraq, moved forward into northern Iraq: the Indian 10^th Division’s Indian 20^th Brigade Group launched a feint from Mosul, and Major General C. O. Harvey’s Indian 8^th Division, in the form of Brigadier D. D. Gracey’s Indian 17^th Brigade Group (1/12^th Frontier Force Regiment and 5/13^th Frontier Force Rifles) advanced into the far north-east of Syria (the Bec du Canard, or Duck’s Bill, province), capturing a long length of railway intact and large stores of arms and ammunition whilst sustaining no casualties. The Vichy French forces withdrew westward along the railway linking Mosul and Aleppo, and Slim detached some of the Gurkha and Lancers force to head northward from Raqqa on the Euphrates river. They were involved in a skirmish at the Euphrates river crossing at Jerablus near the border with Turkey.

By 8 July, the Indian 10^th Division was advancing on Aleppo, thus threatening the rear of the main Vichy forces around Beirut. The Vichy French position had become untenable, provoking Général Henri Dentz, the Vichy French commander, to request an armistice. Negotiations began on 11 July, and the armistice terms were signed on 14 July.