The moves in Diyala province reflect mixed views on a movement that began in 2007 among Sunni tribes in western Iraq who revolted against Al Qaeda in Iraq and joined the Americans in the fight against the terrorist network.
US officials credit the rise of such groups, known variously as Awakening Councils, Sons of Iraq and Popular Committees, with helping rout Al Qaeda.
But Iraq's government is suspicious of such groups, fearing their decision to break with the insurgency was a short-term tactic to gain US money and support. The government fears they will eventually turn their guns against Iraq's majority Shias.
The effort in Diyala, northeast of Baghdad began last month as US and Iraqi forces launched an operation against Al Qaeda and other extremists in that region.
Mullah Shihab Al Safi, commander of Sunni fighters in Diyala said that many senior leaders of his group had been detained and fighters evicted from their offices. He gave no figures. Another senior commander said security forces evicted his men from all but seven of some 100 offices in Diyala. He spoke on condition of anonymity because he feared arrest.
The US military confirmed the Diyala actions but gave few details. Fighters were only pushed out of buildings they did not own, a military spokesman, Capt Matt Rodano, said.
Although there has been no general crackdown on Sunni volunteers elsewhere, some leaders outside Diyala have been arrested in western Baghdad and south of the capital — both one-time Al Qaeda strongholds.
Government officials would not comment on specific claims about the push in Diyala. But aides close to Prime Minister Nuri Al Maliki, a Shia, said the government was not willing to tolerate the existence of armed groups with "blood on their hands."
"The continuation of the Awakening Councils as they are now is unacceptable," said Ali AlAdeeb, a close Al Maliki aide and a senior member of his Dawa Party.
A top Iraqi security official with access to classified information said authorities were especially suspicious of the Diyala groups because many of their estimated 14,000 fighters had been members of Al Qaeda in Iraq.
But acting against the Sunni movements could alienate the once-dominant minority Sunni Arabs at a time when overtures to them appear to be making headway.
"We fought the Americans for four years and we fought Al Qaeda, too," said Al Safi, a former Iraqi army commando during Saddam Hussein's regime who fought in the 1980-88 Iraq-Iran war.