U.S. planes bombed Sunni Muslim fighters in the volatile city of Fallujah on Wednesday, and separate roadside bombs killed two U.S. soldiers in continuing violence across Iraq, U.S. officials said.

The morning airstrike in Fallujah was aimed at a "command and control headquarters" where militants plotted attacks against U.S.-led forces, a military statement said. On Monday, seven Marines were killed by a car bomb outside Fallujah in the deadliest attack against American forces since April 29.

Initial assessments indicated that what the military called a "precision strike" resulted in no civilian casualties, but casualty figures for the fighters could not be confirmed immediately, the statement said. The statement said U.S. forces launched the airstrike after "multiple sources of intelligence were used to confirm the presence of the enemy forces."

An Iraqi Health Ministry spokesman, Saad Amili, said two people were killed and 23 wounded in the attack, although it was unclear whether those figures included combatants.

The bombing in Fallujah represented an escalation of tensions in the Sunni-dominated area. In April, U.S. officials turned over responsibility for protecting the city to Iraqi security forces as part of a negotiated settlement to end street fighting involving U.S. troops.

U.S. officials believe that Fallujah is the base of operations for Abu Musab Zarqawi, a Jordanian sought in Iraq for coordinating anti-American attacks. The city is effectively off-limits to foreign journalists and aid workers, who face the threat of kidnapping and death.

The roadside bomb attacks on U.S. forces took place before dawn, according to U.S. military officials. The first occurred about 1:45 a.m. in Balad, a town north of Baghdad, killing a soldier from the 13th Corps Support Command and injuring another. The second occurred about 5:30 a.m. in eastern Baghdad, killing one soldier and injuring two.

Also on Wednesday, a convoy carrying employees of DynCorp Inc., a Reston-based security firm, was ambushed north of Baghdad. Three Iraqi subcontractors were killed and three American employees wounded, according to Mike Dickerson, DynCorp's director of media relations. Dickerson said the Americans sustained relatively minor injuries.

On Aug. 29, six people were killed when a DynCorp office in the Afghan capital, Kabul, was bombed.

Security officials in Baghdad said five people were killed when a convoy with security personnel from another firm was attacked Wednesday afternoon in the capital.

Special correspondent Bassam Sebti and researcher Robert E. Thomason in Washington contributed to this report.

A military vehicle burns after an attack on a convoy in Baghdad. Violence continued across Iraq, U.S. officials said.