Fresh from his success in securing the fall of Baghdad, regional British Commander-in-Chief Sir Frederick Stanley Maude barely paused before launching the Samarrah offensive further north to consolidate the new Anglo-Indian position at Baghdad, at present threatened by some 10,000 troops to the north of the city.
The Samarrah Offensive, which included the Battle of Istabulat, was launched in mid-March 1917 with 45,000 frontline troops. Operations lasted for approximately six weeks before being called off until the autumn.
Khalil Pasha, the Turkish commander opposing Maude, had 10,000 troops to the north of Baghdad. He also expected to be reinforced by Ali Ishan Bey's 15,000 troops, who were retreating from Persia after being defeated by the Russians.
Maude decided that the British could not advance further north until they had captured the Samarrah railway, which was over 100 miles north of Baghdad.
The Battle
To capture Samarrah, Maude devised a four-pronged plan:
- Launch a series of small-scale attacks up the River Tigris.
- Prevent the Turks from flooding the plains around the Euphrates River.
- Prevent Ali Ishan Bey's force of 15,000 from joining up with Khalil Pasha's forces.
- Conduct holding operations in the West.
The Turks fought fiercely against Maude's advance.
On March 13, just two days after the fall of Baghdad, the British launched a successful raid on Turkish lines north of the city, forcing the Turks to retreat 22 miles to the junction of the Tigris and Adhaim rivers.
On March 19, the British captured Fallujah, which prevented the Turks from flooding the plains and significantly harassing the British advance.
On March 25, the British attempted to encircle Ali Ishan Bey's 15,000 men, but the Turks were able to repel the attack. Ali Ishan Bey then moved west to meet up with 5,000 Turkish troops at Dogameh, which had been sent down the Tigris to meet him.
As a consequence of the Battle of Dogameh, the Turkish defensive line fell back to the junction of the Tigris and Adhaim rivers. The British, under General William Marshall, attacked the new Turkish position on April 18, 1917 (after a hasty detour to assist besieged cavalry at Shiala).
Khalil Pasha's force had withdrawn a further 14 miles north to Istabulat. They took up formidable positions between the Tigris and the Al Jali Canal. The Samarrah railway ran between these two bodies of water.
Undeterred by the difficulty of the task, Maude continued the offensive on April 21, attacking at several points near the river.
Heavy fighting saw some positions change hands several times. On the morning of April 22, the defending Turks retreated to a ridge just 6 miles from the railway. Casualties were roughly equal, with each side suffering 2,000 losses.
Continuing British attacks, coupled with the arrival of reinforcements, persuaded the Turks to cede Samarrah on April 23. The town and its railway were now in British hands.
The Samarrah Offensive was a success in that it achieved its objective. However, it was also a costly victory for the British.
Casualties during the offensive as a whole were estimated to be around 18,000, with an additional 40,000 soldiers lost to disease.
The heavy casualties suffered by the British during the Samarrah Offensive forced Maude to pause and regroup before launching a further advance in the autumn.
The relative numerical weakness of Maude's force also meant that no resources could be redirected to the Western Front. The War Office in London, led by Sir William Robertson, wanted to scale down operations in Mesopotamia, but this desire was not fulfilled.