Iraqi officials say two car bombs exploded minutes apart in a busy Baghdad market in a mainly Shiite area Sunday, killing at least 34 people and wounding 50. A few hours later, a suicide bomber blew himself up on a minibus in northwest Baghdad, killing at least six people. Meanwhile, political bloc of radical Shi'ite cleric Moqtada al-Sadr says it will withdraw from Iraq's government Monday to protest PM's failure to support a timetable for US troops' withdrawal. From northern Iraq, VOA's Margaret Besheer has more.

The back-to-back car bombs exploded in a busy market in a Shiite area of southwestern Baghdad that was full of morning shoppers. Many women and children were among the casualties.

A few hours later, police say a suicide bomber blew himself up on a minibus killing and injuring several people. Many of the wounded suffered severe burns.

Police officer Mohammed Jassim said a minibus coming from the Bab al-Mu'dham neighborhood heading to Kazimiyah exploded while he was standing in front of the courthouse. He says there were many casualties.

Kazimiyah is a Shiite area of the capital where there is a prominent shrine.

The latest attacks on Shiite targets come a day after a car bomb exploded in the southern Shiite holy city of Karbala not far from one of the sect's holiest sites - the Imam Hussein shrine. More than 40 people were killed and dozens more were injured.

Meanwhile, north of the capital, two British military helicopters crashed, killing two service members and seriously injuring a third.

British Defense Secretary Des Browne said in a statement that preliminary indications are the crash was an accident and not the work of insurgents. A U.S. military statement said initial reports indicate it was the result of a mid-air collision.