This is just in from CNN:
BAGHDAD, Iraq (CNN) -- An explosion rocked a municipal building Tuesday in Baghdad's Sadr City neighborhood, killing six Iraqis, two U.S. soldiers and two civilian U.S. Embassy employees, officials said.
The U.S. military said troops detained a suspect in connection with the attack. The person was captured "fleeing the scene and tested positive for explosive residue," the military said.
The embassy official said the American civilians include "a direct hire civilian employee of the Department of State and a Department of Defense civilian employee."
The blast occurred during a meeting of the district advisory council in Sadr City, and U.S. troops were in the area, an Iraqi Interior Ministry official said.
The U.S. military confirmed the deaths, saying an American-led coalition soldier and three council members also were wounded. There have been 4,106 U.S. service members killed since the Iraq war began.
Ten Iraqis were wounded in the blast, an Interior Ministry official said.
The military blamed Iranian-backed militants that U.S. officials call Special Groups for Tuesday's attack.
"This was the fourth meeting of this district council, led by hard-working Iraqis determined to make a difference and set Sadr City off on the right path. Special Groups are afraid of progress and afraid of empowering the people," said Lt. Col. John Digiambatista of the 4th Infantry Division.
The explosion follows a Pentagon report issued Monday that touted a sharp decrease in violence in Iraq in recent months.
Sadr City is the stronghold of Shiite cleric Muqtada al-Sadr and has seen some of the capital's most intense fighting between Shiite militia members and security forces.
Al-Sadr recently announced his intention to develop a fighting force that would battle U.S.-led forces in Iraq.
A truce was reached last month between the government and al-Sadr's followers, ending weeks of fighting and allowing the Iraqi army to enter Sadr City, but violence persists.
Tuesday's blast comes after gunmen stormed the house of the head of Abu Dsheer City Council on Monday night and fatally shot him.
Mehdi Alwan was an al-Sadr supporter. Abu Dsheer is a Shiite enclave in southern Baghdad's predominantly Sunni Dora district.
The names of the two killed are being withheld pending notification of their families. Our thoughts go out to them.