Baghdad ? Three years ago, the U.S. thinned out its presence in Baghdad and Iraqi forces could not stem the tide of sectarian fighting. By the end of June, Iraq’s forces will again be in control of their cities — and many Iraqis wonder whether they are up to the task.

Publicly, the U.S. military insists it has full confidence in Iraq’s army and police to cope with security challenges after the June 30 deadline for American combat troops to leave Baghdad, Mosul and other cities.

Privately, however, some U.S. and Iraqi officials acknowledge no one can say with certainty whether Iraq’s police and soldiers can perform until they assume the responsibility.

Many Iraqis fear that Sunni and Shiite extremists are lying low, waiting for the Americans to pull back, and won’t wait long to mount a challenge.

“I think that there are terrorist groups that will try to carry out some terrorist and criminal activities in the coming period during and after the withdrawal of U.S. forces from the cities,” Interior Minister Jawad al-Bolani said last week.

“Despite the existing security challenges and threats, I think that our security forces should be given the confidence and the chance to prove their capability,” he added.

Iraqi forces proved incapable of meeting the challenge when the U.S. drew down its presence in the cities in 2005 and 2006, when U.S. policy called for handing responsibility to the Iraqis as quickly as possible.

As Shiite-Sunni fighting boiled over in Baghdad’s streets, the White House reversed course and ordered the U.S. troop surge of 2007. That helped curb the violence, now at some of its lowest levels of the war.

But last month’s spate of high-profile bombings in Baghdad alarmed many Iraqis. Although major bombings have fallen about 50 percent since April, the attacks have left many Iraqis uneasy about what will happen when the Americans pull out of the cities — especially Baghdad and Mosul, where al-Qaida and other Sunni groups still operate.

“As a matter of principle, nobody wants foreign forces to stay in the country, but the current bloodshed acts proved that Iraqi forces are not ready yet to be responsible for security,” said Haider Abbas, 45, a Shiite teacher in east Baghdad.

“Murders and explosions are taking place while there are U.S. troops inside the city,” he added. “What will happen when they leave?”

U.S. commanders have said some American troops will remain in Baghdad after June 30 as advisers. Some officials have suggested they could number about 2,500.