The Iraqi government has imposed an immediate curfew in Baghdad through Sunday morning.
News reports say no people or vehicles will be permitted on the streets of the Iraqi capital from Friday evening until the end of the curfew.
It was unclear why the curfew was imposed, but it came at a time when U.S. and Iraqi troops are engaged in a large-scale security operation in Baghdad.
In other news, Iraqi authorities say gunmen shot dead the brother-in-law of the new judge in charge of the genocide trial against former Iraqi leader Saddam Hussein. Kadhim Abdul-Hussein was in his car in Baghdad when gunmen opened
And Iraqi officials say security forces detained 60 suspects in an an operation against insurgents in the town of Baquba.
Separately, Iraqi officials say a top leader of the umbrella militant group the Mujahadeen Shura Council was arrested this week in the northern city of Mosul. The officials say militant leader Mahmood Yahia Hussein was detained in a raid, along with a top aide. The Mujahadeen Shura Council includes al-Qaida in Iraq.