Fighting between security forces and Shi'ite militiamen last month has driven civilian deaths in Iraq to their highest level in more than six months, government figures showed on Tuesday.
Britain responded to renewed violence in the southern city of Basra by delaying plans to bring home 1,500 of its 4,000 troops in Iraq.
A total of 923 civilians were killed in March, up 31 percent from February and the deadliest month since August 2007, according to data compiled by Iraq's interior, defence and health ministries and obtained by Reuters.
The figures are a blow to the Iraqi government and the United States, which have pointed to reduced overall levels of violence in recent months as evidence that a major security offensive has made significant progress.
Hundreds of people were killed and many more wounded in last week's fighting after Prime Minister Nuri al-Maliki ordered a crackdown on Shi'ite militiamen in Basra. Many of the dead were civilians caught in the crossfire.
Basra was relatively calm for a second straight day on Tuesday after Shi'ite cleric Moqtada al-Sadr called his fighters off the streets on Sunday. A Reuters reporter in the city said more shops were open and people were out on the streets although many schools and government offices were still shut.
In Baghdad's Sadr City, the slum of 2 million people that forms the cleric's main stronghold in the capital and location of much of last week's combat, the situation was tense but there were no reports of major clashes.
The Red Crescent said U.S. and Iraqi security forces prevented a convoy carrying food, blood and medicine supplies from entering the area due to the security situation.
Maliki declared the military operation a success: "After maintaining stability and security, the security plan succeeded in its goals in imposing the law in the province of Basra," he said in a statement.
The prime minister, who had led the operation personally from Basra, returned to Baghdad on Tuesday, said Defence Ministry spokesman Major-General Mohammed al-Askari said.
