Three U.S. soldiers were killed by a roadside bomb Friday south of Baghdad, the U.S. military said.

The troops were killed when their vehicle struck a roadside bomb in Babil province, a military statement said.

Two U.S. soldiers also died Thursday in a roadside blast in south-central Baghdad, the military said.

The Pentagon reported the deaths of three Marines and a soldier, all killed in combat earlier this week.

Eleven American troops have died this week in Iraq -- all but one in hostile action.

The number of U.S. military deaths in the Iraq war stands at 2,415.

In other violence, three insurgents were killed Thursday in fighting with American soldiers near Samarra, north of the capital, the U.S. military said. A citizen was wounded during the firefight.

The fighting got under way when troops from the Task Force Band of Brothers apprehended three "known" bomb placers, the military said in a statement.

From a rooftop, people wielding small arms fired at the troops as they were taking way the detainees, officials said.

"The troops suppressed the rooftop fire and entered and killed the three attackers from the rooftop," the statement said.

Also Thursday, a female bomber removed an explosives-laden vest after being denied access to a Baghdad courthouse and left it in a bag outside the building, where it exploded and killed at least nine people, a witness told the Iraqi Interior Ministry.

The blast, outside the eastern Baghdad courthouse on busy Palestine Street, wounded 46 others, the ministry said.

The violence took place as a report from retired Army Gen. Barry McCaffrey said the American strategy in Iraq is "painfully but gradually succeeding" and noted that U.S. troops will be needed in Iraq for another three to five years. (Watch new ideas on a U.S. exit strategy -- 2:11)

Elsewhere Thursday in Baghdad, Iraqi army Brig. Gen. Mohammed Abdul Latif was gunned down in the western Yarmouk neighborhood as he drove to work, the Interior Ministry said.

In Tikrit, Saddam Hussein's ancestral homeland, police said they found 16 bodies Thursday. All were shot in the head, and police said they were unable to identify the bodies.

Also in Tikrit, gunmen shot and killed a police officer in a drive-by shooting, police said. Another police officer was wounded.

In Ramadi, west of the capital, eight insurgents were killed in a firefight with American Marines, the U.S. military said.

In Iskandariya, south of Baghdad, police found two bodies dumped in plastic bags near a bridge Thursday, a police spokesman said. The bodies have not been identified.