BAGHDAD — Clashes erupted between gunmen and U.S. and Iraqi forces around a Shiite mosque in western Baghdad before prayers today, and two suspected insurgents were killed, the American military said.

After killing the insurgents, soldiers searched nearby buildings, found chemicals believed to be bomb-making materials and detained an Iraqi civilian, the military said. Iraqi soldiers searched the Ali al-Baiyaa mosque, but found no weapons or suspects.

Also today, the U.S. military announced the death of a Marine in a rocket attack the night before on a base south of the capital. Two others were wounded in the attack on a U.S. base in Mahmoudiya, about 20 miles south of Baghdad, a statement said.

At least 3,315 members of the U.S. military have died since the Iraq war started in March 2003, according to an Associated Press count.

Meanwhile, U.S. forces killed eight suspected insurgents and captured 41 in several raids across Iraq today, the military said.

BAGHDAD — Making his third visit in four months to Iraq, Defense Secretary Robert Gates took a decidedly stronger tone as he warned the troubled nation's leaders that American patience is wearing thin.On his unannounced trip, the Pentagon chief said Iraq's leaders have to move faster to bring together the warring factions.Gates had planned to take a look today at a key piece of the Bush administration's new anti-insurgency strategy, a joint US-Iraq security post where American and Iraqi forces live and work together to try to stop the violence that is ripping Baghdad.That tour, however, was abruptly canceled, and defense officials traveling with Gates said it was because his meeting with top U.S. commanders went longer than anticipated."The clock is ticking," Gates told reporters Thursday."I know it's difficult, and clearly the attack on the council of representatives has made people nervous, but I think that it's very important that they bend every effort to getting this legislation done as quickly as possible."A suicide bomber infiltrated the parliament building in the heavily fortified Green Zone a week ago, dealing a blow to the U.S.-led effort to pacify the capital's streets.