BAGHDAD -- Insurgents killed three American soldiers in the Baghdad area yesterday and fired mortars near the Defense Ministry in a spree of violence that killed at least 27 Iraqis as politicians began work on forming a new government.
The largest Sunni Arab party raised new allegations of sectarian killings, one of the most urgent issues facing the new Iraqi leadership.
US Ambassador Zalmay Khalilzad said the next government must decommission sectarian militias and integrate them into the national armed forces, warning that the armed groups represent the ''infrastructure for civil war."
Yesterday's deaths raised to eight the number of US troops killed in the past two days.
At least 61 American service members have died in April, putting it on track to pass January -- with 62 -- as the deadliest month this year. It represents a jump over March, which with 31 deaths was the lowest monthly toll for the Americans since February 2004.
The three solders were killed yesterday when their vehicle hit a roadside bomb northwest of capital, the US command said.
Twenty-seven Iraqis also died in violence yesterday, including seven killed when three mortars hit just outside the heavily guarded Green Zone in Baghdad, not far from Iraq's Defense Ministry.
At least eight other mortars or rockets exploded at about the same time on the other side of the Tigris River in Baghdad, without causing injuries, police said.
In the evening, another mortar hit a home in southern Baghdad, killing a man and wounding two of his relatives. In drive-by shootings in a nearby district, a schoolteacher was gunned down outside her home and a car mechanic was killed in his shop.
The violence underlined the challenge as prime minister-designate Jawad al- Maliki began yesterday the tough task of assembling a Cabinet out of Iraq's Shi'ite, Sunni, and Kurdish parties.
Maliki, a Shi'ite, has 30 days to do it, but the parties are under enormous pressure -- from Americans and even Shi'ite religious leaders -- to move quickly without the often intractable haggling over ministries.
The United States is hoping the new government will unify Iraq's divided factions behind a program aimed at reining in both the Sunni-led insurgency and the Shi'ite-Sunni killings that escalated during months without a stable government.
Khalilzad, a key player in tortuous political negotiations since Iraq's Dec. 15 elections, repeated his call for the quick creation of a Cabinet of ''competent" ministers -- implying those chosen for their skills and not sectarian or political ties.
He also issued a warning yesterday against militias, calling them ''a serious challenge to stability in Iraq to building a successful country based on rule of law."
''There is a need for a decommissioning, demobilization, and reintegration plan for these unauthorized military formations," he said at a news conference with the Iraqi president, Jalal Talabani, in the northern city of Erbil.
Sunnis say Shi'ite militias have infiltrated the Interior Ministry, which is controlled by the biggest Shi'ite party, and used death squads to kill Sunnis. Sectarian violence has flared since the Feb. 22 bombing of a Shi'ite shrine in Samarra, north of Baghdad.
But the killings have gone both ways. Police said the bodies of six Shi'ites were found yesterday in the mainly Sunni district of Azamiyah in Baghdad, their hands and legs bound and their bodies showing signs of torture. Two more -- their identities unknown -- were found in a mixed district south of Baghdad.
The head of the Azamiyah district council, Sheik Hassan Sabri Salman, said relatives identified yesterday the bodies of 14 Sunnis kidnapped last week. The bodies, he said, were handcuffed with signs of torture. Police did not confirm the deaths.
The Iraqi Islamic Party, the main Sunni faction in Parliament and a likely participant in the next Cabinet, warned of ''the repercussions of sectarian cleansing." It urged the new government to stop ''the criminal gangs" involved in the killings.
Control of the Interior Ministry will be a key question. The Shi'ite Supreme Council for the Islamic Revolution in Iraq, which currently holds it, appeared to be under pressure to give it up. SCIRI ran the feared Badr Brigade militia during Saddam Hussein's rule but insists that the group has given up its arms, an assertion many Sunnis reject.
Uprooting militia power will be difficult for any government. Maliki has vowed to implement a law that would integrate them into the security forces, but there is little guarantee that the forces -- once in the army or police -- would then drop their loyalty to their former sectarian commanders.