Baghdad: US troops captured an alleged Shiite militia leader and three other suspects in a raid south of Baghdad, the US military said on Friday.

The operation took place late on Thursday in the Mashru area, the military said in a statement.

The main suspect was believed to be a "special groups" leader, language the military uses to describe Shiite Muslim militias allegedly backed by Iran.

The US says the groups have broken ranks with Muqtada Al Sadr's Mahdi Army. The radical cleric in August called a six-month ceasefire, which is due to expire later this month.