Gunmen in Iraqi police commando uniforms have stormed a private security company in Baghdad, taking dozens of employees hostage.
The gunmen seized as many as 50 employees of the Al-Rawafid company from its offices in an eastern Baghdad neighborhood, Zayouna.
Officials at Iraq's Interior Ministry said the ministry was not involved. It did not identify the attackers.
In other violence on Wednesday, Iraqi police said gunfire and roadside bombs, including one that hit an Interior Ministry security convoy, killed at least 11 people in Baghdad.
Security patrols found the bodies of at least 20 men, most of them in an abandoned vehicle in Amiriyah a predominantly Sunni Muslim neighborhood of the capital.
Iraqi officials say most of the men had been bound and strangled.
The grisly discoveries come during a surge in sectarian violence since last month's bombing of a golden-domed Shi'ite shrine in Samarra.
In other news, the U.S. military announced that an American soldier and an American marine died in separate incidents north of Baghdad.
The new violence came as the U.S. State Department issued its assessment of human rights around the world, noting that reports of killings by the U.S.-backed Iraqi government or its agents increased in 2005.
The U.S. has urged Iraq's political factions to form a national unity government which, it believes, would help stem the violence.
Iraqi political parties are continuing to work on forming a new government.
President Jalal Talabani has ordered parliament to convene on Sunday, in order to meet a deadline mandated by the nation's post-Saddam constitution. However, the Shi'ite alliance (the Supreme Council for the Islamic Revolution in Iraq) of Prime Minister Ibraham al-Jaafari has asked Mr. Talabani to delay the opening.
Kurdish and Sunni Arab politicians oppose Mr. al-Jaafari continuing as prime minister. Mr. al-Jaafari has said he will not be pressured into abandoning his campaign for a second term.