A U.S. aircraft attacked a group of men believed to be members of a government-allied Sunni paramilitary group as they were planting a roadside bomb north of Baghdad, killing one and wounding two, the U.S. military said Friday.

The attack, which occurred Thursday night near Taji, followed last weekend's crackdown on another Sunni group in Baghdad, which began when the commander was arrested on criminal and terrorism charges.

A U.S. statement said the airstrike was launched after four gunmen were seen planting a roadside bomb near Taji, site of a large U.S. air base about 12 miles north of Baghdad.

One of the gunmen was killed and the two wounded were captured in a nearby house, the U.S. said. They were handed over to Iraqi police.

"Initial investigation revealed that at least one of the men had served in the Sons of Iraq program," the statement said.

Sons of Iraq, also known as Awakening Councils, are Sunnis who broke with the insurgents and now work with the army and police to provide security in their areas. The Shiite-led government is suspicious of the councils and believe some of them may be infiltrators still working for the insurgents.

"While we value our Sons of Iraq brothers, these men had broken faith with their fellow Sons of Iraq, the Iraqi people and us," said Maj. Gen. Daniel Bolger, commander of U.S. forces in the Baghdad area.

U.S. commanders credit the Awakening Councils with playing a major role in turning the tide against Al Qaeda and other insurgent groups following the U.S. troop surge of 2007.

But the Thursday attack and last weekend's uprising in central Baghdad suggest major problems in the 90,000-member paramilitary program.

Last October the U.S. transferred control of the paramilitaries to the Iraqi government, which promised to take 20 percent of them into the army or police and pay the rest until they could be found civilian jobs.

But delays in pay and a series of arrests led to fears among some Awakening Council leaders that the Shiite-run government intended to sideline the groups as U.S. influence wanes.

Last Saturday, members of the Awakening Council in the Baghdad's slum neighborhood of Fadhil launched an uprising after police arrested their leader on charges of terrorism, murder, extortion and leading a cell loyal to Saddam Hussein's banned Baath party.

In an interview Thursday with Iraqi state television, Prime Minister Nouri al-Maliki said the Fadhil crackdown was not politically motivated and followed a six-month investigation that tied the commander to crimes and subversion.

Al-Maliki said the crackdown sends a message that those who want to undermine the political process "will face the same fate."