Marines and Iraqi security forces continued their operations in and around Haditha on Sunday, rounding up some three-dozen men in what the U.S. military has dubbed Operation New Market.

The Haditha raids, a follow-up to the large-scale offensive conducted earlier this month in the western deserts near the Iraq-Syria border, have so far resulted in at least 14 suspected insurgents killed, officials said.

Marines of 3rd Battalion, 25th Marines have also confiscated more than 300 mortar rounds, two 155 mm artillery rounds and several rocket-propelled grenade launchers in the raids, according to Multi-National Forces-Iraq officials in Baghdad.

One of the weapons caches was seized in a neighborhood school, officials said.

The raids have been backed up by airstrikes, including one Thursday night in which a laser-guided bomb was dropped on a building from which insurgents were firing. The building was leveled, officials said.

According to wire service reports, as many as 1,000 U.S. and Iraqi soldiers are participating in the sweep. Haditha, a town of about 100,000 people along the Euphrates River northwest of Baghdad, has long been a trouble spot.

Insurgents have attacked the area’s public infrastructure and U.S. forces, many of whom are based in a dam along the Euphrates.

The town sits along one of the major routes between Syria and central Iraq; U.S. officials have said they believe foreign fighters and supplies have been smuggled across this route from Syria.