British forces have been defeated in Basra, an American official said yesterday.

A senior American intelligence official told the Washington Post that British commanders had allowed militias loyal to three Shiite Muslim groups take control of the city’s streets. “The British have basically been defeated in the South,” he said. The report said a contingent of 500 British troops based at Basra Palace were “surrounded like cowboys and Indians.”

The rebuke highlights the increasing violence in Basra, one of four provinces handed over to British control after the American-led invasion of Iraq in 2003. Three of the four provinces have been pacified and handed back to local leaders; Basra, the most populous, is due to be returned by the end of the year.

Major Mike Shearer, a spokesman for British command in Basra, rejected the suggestion that British troop levels in the province, which are now down to 5,500, had been cut too fast. “Basra’s crime levels are half the level of Washington,” he said. “What we are trying to do is get the security situation to a manageable level where Iraqi solutions can be delivered to Iraqi problems.”

A second British official in Basra said the American criticism was misplaced. “Yes, there’s violence, and yes, there’s corruption,” he said. “But the electricity directorate, the water directorate, the government structures still work. The Iraqis down here can work their way through the violence.”

Prime Minister Brown told President Bush at their meeting at Camp David last week that British troops planned to hand over responsibility for Basra to local leaders within months, but that the decision was in the hands of British commanders.

Britain’s former governor of Basra, Hilary Synnott, said the American criticism was payback for British claims two years ago that Basra was a success while Washington had failed in Baghdad. “It’s not so long ago that some members of the British government were boasting that Basra was doing very well, better than Baghdad. That was very unwise.”

Brigadier General Anthony Hunter-Choat, a security director for Iraq’s reconstruction program, said America had initially backed the British “softly, softly” approach to security in Basra, by which power was devolved to tribal leaders, rather than ruling from the top down. “The Americans thought the British were highly successful,” he said. “Now they’ve started to think that the people the British used to keep the place going are not the right people to hand Basra over to.”

A think-tank report, quoted in the report, said the legacy of British rule in Basra was “the systematic misuse of official institutions, political assassinations, tribal vendettas, neighborhood vigilantism, and enforcement of social mores, together with the rise of criminal mafias.” A former British defense official, now working in Baghdad, said London’s push to withdraw forces had been criticized at the “highest levels” in Washington. America “has been very concerned for some time now about a) the lawless situation in Basra; and b) the political and military impact of the British pull back,” he said.

[Four more American troops and a British soldier have died in attacks, military officials said yesterday, the Associated Press reported. The spate of recent American deaths — 19 so far in August — seems certain to intensify the debate over American progress to calm Iraq and gain ground against militants ahead of a key September report to Congress.

American deaths had dropped slightly in July to 79 — the lowest monthly tally since 70 were killed in November. Before July, more than 100 American forces died each month in the April-to-June period.

American commanders say rogue Shiite militias have stepped into the gap left as Sunni insurgents have been pushed back, and are now responsible for most attacks on Americans in Baghdad and surrounding districts.]