BAGHDAD, Iraq — Bombs rocked a teeming quarter of Baghdad and a sex-film theater in Mosul on Wednesday, reportedly killing at least three Iraqis and wounding dozens. In a string of ground clashes, the U.S. military said they killed nine Iraqis on one of the bloodiest days of combat in weeks.

The nine deaths were all in the region around Tikrit, Saddam Hussein’s hometown. U.S. troops aborted two ambushes by anti-American forces, killing five Iraqis, and came under fire elsewhere in exchanges that left at least four Iraqis dead.

More than five months after the ouster of Hussein’s government, the troops who are here — almost all Americans — face a daily threat of homemade roadside bombs, mortar attacks and small-arms ambushes.

For the first time Wednesday, U.S. soldiers in central Baghdad were seen deploying bomb-disposal robots to check a suspicious object at an underpass. That proved harmless, but at about the same time three miles to the northwest, a bomb meant to catch a passing U.S. motorized patrol exploded instead as two buses rolled by.

The blast, in the old Tigris riverside district of Azamiyah, sent shrapnel ripping through the buses and caused one to crash into a tree. At least one Iraqi was killed and 18 were wounded, police and hospital officials reported. Five of the injured were in critical condition, hospital officials said.

In the northern city of Mosul, a bomb exploded in a movie theater showing foreign sex films, and witnesses said two people were killed and seven wounded. Religious and political groups have warned cinema owners against showing such films after censorship ended following the collapse of Hussein’s regime.

South of Tikrit near the town of Balad, seven Iraqis attacked an oil pumping station guarded by troops of the U.S. 4th Infantry Division. The Americans called in an AC-130 gunship, whose heavy weapons fire killed at least three Iraqis, reported division spokeswoman Maj. Josslyn Aberle. A fourth was seriously wounded.

In a second clash near Balad, a U.S. patrol killed three Iraqis waiting in ambush with small arms and rocket-propelled grenades, the military said.

Another U.S. patrol in the same area opened fire on three men trying to bury a homemade bomb — a mortar shell that was probably to be triggered remotely — on a highway used by U.S. convoys. Two Iraqis were killed in the firefight, Aberle said.

In a fourth firefight south of Tikrit, American soldiers came under fire, pursued the attackers to a house, and killed one Iraqi, the military said.

Copyright ©2003 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.