Gunmen wearing commando uniforms of the Shiite-dominated Interior Ministry stormed an Iraqi security company that relied heavily on Sunni ex-military men from the Saddam regime, spiriting away 50 hostages.
The ministry denied involvement and called the operation a "terrorist act."
Police and the U.S. military, meanwhile, reported finding the bodies of 24 men Wednesday who were garroted or shot in the head, most of them in an abandoned bus in a tough Baghdad Sunni neighborhood.
They also reported the deaths of at least 14 others across Iraq, including a U.S. soldier and a Marine.
The Sunni minority, which was dominant in the country under Saddam Hussein, has complained bitterly that it is under attack from death squads associated with the Interior Ministry, in charge of Iraq's police. And, over the past two weeks, since the bombing of a Shiite shrine in Samarra, violence has become increasingly sectarian. Nearly 600 people have been killed since Feb. 22.
Many of the dead in that period were Sunnis, killed at close range after apparently being captured by overwhelming numbers of attackers. The nature of the killings suggested that a well-armed and organized force carried out the attacks.
There have also been repeated attacks against the Shiite-led security forces. Interior Minister Bayan Jabr and one of his assistants may themselves have been targets of assassination attempts Wednesday.
A bomb hidden under a parked car detonated as police from Jabr's protection force were driving through Baghdad, killing two officers and wounding a third, police said. Four bystanders were injured.
And gunmen attacked the convoy of Interior Ministry Undersecretary Hekmet Moussa in west Baghdad, killing two bodyguards and injuring two others, police said.
Neither Jabr nor Moussa were in the convoys, reports the AP.
An intense movement of NATO aircraft was reported at Poland's Rzeszow airfield near the Ukrainian border