RAMADI, August 13, 2005 (Reuters) - An attack on a U.S. military patrol followed by heavy U.S. gunfire left 15 Iraqis dead and 17 wounded in a town west of Baghdad, residents said on Saturday.

Residents of Nasaf, a town just outside Ramadi, west of Baghdad, said a roadside bomb exploded next to a U.S. armoured patrol as it passed near the Ibn al-Jawzi mosque shortly after prayers on Friday.

Following the explosion, U.S. troops opened fire, the residents said, shooting towards those emerging from the mosque.

Munem Aftan, the director of Ramadi General Hospital, said 15 people were killed, including eight children, and 17 wounded.

The U.S. military denied troops had opened fire indiscriminately.

"Indiscriminate U.S. fire on civilians? No, nothing even resembling this occurred," Captain Jeffrey Pool, a Marines spokesman in Ramadi, said in an e-mailed reply to questions.

He did not say whether an attack on a U.S. patrol had occurred or whether any U.S. troops were wounded.

The death toll was initially reported as two dead, but doctors said it had risen sharply overnight, with several of the severely wounded succumbing to their injuries.

Iraqi civilians frequently complain that U.S. troops open fire indiscriminately after they are attacked. The U.S. military says it does everything possible to avoid civilian casualties and is careful to respond to attacks in a measured fashion.

Human rights groups have documented scores of cases in which civilians have been shot and killed after approaching U.S. military roadblocks too quickly, or not following instructions to keep away from U.S. military convoys as they pass.

Roadside bombs — large or small amounts of explosives buried in the side of the road and detonated as U.S. vehicles pass — are the biggest killer of U.S. troops in Iraq.

A U.S. general said on Friday that roadside bomb attacks on U.S. supply convoys in Iraq had doubled in the past year, although the number of casualties had declined because of increased use of armoured vehicles.