BAGHDAD, Iraq (AFP) -- A suicide bomber killed at least 12 people and wounded 25 others in an attack on a market in southern Baghdad on Thursday, security officials said.

The bomber targeted a US patrol that was passing through a popular Assyrian market in the confessionally mixed Baghdad district of Dora, officials from the interior and defence ministry told AFP.

The US military said it was awaiting further details amid unconfirmed reports of American casualties.

"Right now we have an initial report of an attack in the area, and a unit is en route to the location," it said in a statement.

Earlier this month 10 people were killed and 37 wounded when a pick-up truck blew up in a wholesale produce market in Dora, a district that until a year ago was one of the city's most dangerous areas.