Baghdad, Iraq ? A suicide bomber unleashed a blast Tuesday in a Baghdad fish market and two Shiite families were found slain north of the capital as violence across Iraq claimed at least 52 lives.

The U.S. military, meanwhile, announced the deaths of nine soldiers and two Marines in what has been a deadly period for American forces in Iraq. The announcement brought to at least 15 the number of servicemembers killed in fighting since Saturday.

Four of the soldiers were killed Monday in Baghdad in separate small-arms fire attacks. Another four were killed the same day in a roadside bomb attack on their patrol northwest of Baghdad. The ninth died Sunday when his vehicle was struck by a roadside bomb west of the capital.

Sunni politicians expressed worries about a new government plan to stop sectarian violence. The plan, announced a day earlier by Prime Minister Nouri al-Maliki, won some praise in parliament Tuesday, but Shiite and Sunni leaders delayed potentially contentious talks to work out its details.

The four-point plan calls for creating neighborhood Shiite-Sunni committees to monitor efforts against sectarian violence. The aim is to overcome the deep mistrust between Sunnis and Shiites.

Many Sunnis remain skeptical that Shiite leaders will allow security forces to crack down more strongly on Shiite militias blamed for killing Sunnis – including some linked to parties in the government.

“I haven’t seen any real desire in the other side. There are militias supported by the government,” said Sunni lawmaker Khalaf al-Alayan.

Al-Maliki’s government has been under intense pressure to put an end to Shiite-Sunni violence that has killed thousands of people this year and raised fears of civil war. This week, gunmen carried out two mass kidnappings in as many days, abducting 38 people in Baghdad – attacks that Sunnis said were carried out by Shiite militias.