Baghdad, Iraq ? U.S. troops went on the offensive from the gates of Baghdad to the Syrian border Tuesday, pounding Sunni insurgent positions from the air and supporting Iraqi soldiers in raids on mosques suspected of harboring extremists.

American and Iraqi forces launched the operations ahead of Ramadan, expected to start at week’s end, in an apparent attempt at preventing a repeat of the insurgent violence that took place at the start of last year’s Muslim holy month.

Clashes broke out in a string of militant strongholds from Fallujah, 40 miles west of Baghdad, northward along the Euphrates Valley to the Syrian border town of Qaim — all major conflict areas.

Some of the sharpest exchanges took place in Hit, 90 miles northwest of Baghdad, where residents and hospital officials said U.S. aircraft attacked two sites, killing two people and wounding five. The U.S. command had no comment.

U.S. helicopters fired on a mosque in Hit on Monday and set it ablaze after the military said insurgents opened fire on Marines from the sanctuary. Scattered clashes were reported overnight, killing at least two Iraqis and wounding 15, hospital official said.

Insurgents attacked an Iraqi National Guard outpost east of Qaim Tuesday, the U.S. military said. The local hospital reported 15 to 20 people were killed.

Seventy miles west of Baghdad, Iraqi troops backed by U.S. soldiers and Marines raided seven mosques in the Sunni insurgent stronghold of Ramadi, arresting a locally prominent member of a clerical association and three other people. They also seized bomb-making materials and “insurgent propaganda” in the mosques, U.S. officials said.

Angry Ramadi residents accused the Americans of breaking down doors and violating the sanctity of mosques.

“This cowboy behavior cannot be accepted,” said cleric Abdullah Abu Omar. “The Americans seem to have lost their senses and have gone out of control.”

An Iraqi woman participates in the weapons-for-cash swap at the Al Jazaer police station in Sadr City, Iraq. Tuesday, followers of radical cleric Muqtada al-Sadr trickled for a second day into police stations in the district to hand in weapons. U.S. and Iraqi troops, meanwhile, launched offensives in Fallujah and Hit in an attempt to quell rebellion before Ramadan begins.

However, the raids followed a surge in insurgent attacks in Ramadi, and the U.S. command accused the militants of violating the sanctity of the mosques by using them for military purposes. Marine spokesman Maj. Francis Piccoli said U.S. troops provided backup for the Iraqi soldiers but did not enter the mosques.

In Fallujah, the focal point for Sunni resistance, residents reported explosions and clashes on the eastern edge of the city Tuesday afternoon. At least five people were killed and four wounded in the blasts, according to Fallujah General Hospital.

A U.S. official, speaking on condition of anonymity, said there are concerns within the U.S. government about a possible rise in insurgent violence around Ramadan, because of an upswing last year — when bombings and rocket attacks accelerated significantly in Baghdad and other areas at the beginning of the holy month.