Baghdad, Iraq ? Insurgents killed three American soldiers Sunday in the Baghdad area 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 leadership.

U.S. 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.”

Sunday’s deaths raised to eight the number of U.S. 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 from March, which with 31 deaths was the lowest monthly toll for the Americans since February 2004. As of Sunday, at least 2,391 members of the U.S. military have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.

The three soldiers were killed Sunday when their vehicle hit a roadside bomb northwest of capital, the U.S. command said.

Twenty-seven Iraqis also died in other violence Sunday, including seven killed when three mortars hit just outside the heavily guarded Green Zone in Baghdad, not far from Iraq’s Defense Ministry. Police Lt. Maitham Abdul-Razzaq said it was hard to identify the seven dead because the powerful blasts and shrapnel severed their limbs and destroyed their identification cards.

At least eight other mortars or rockets exploded about the same time on the other side of the Tigris River in central Baghdad, without causing injuries, police said.

The violence underlined the challenge as prime minister-designate Jawad al-Maliki began on Sunday the tough task of assembling a Cabinet out of Iraq’s Shiite, Sunni and Kurdish parties.

President Bush called al-Maliki, the Iraqi president and the parliament speaker – all named on Saturday – and urged the quick formation of a coalition government.

“They have awesome responsibilities to their people,” Bush told military families in the mess hall at the Marine Corps Air Ground Center. “Democracy in Iraq will be a major blow to the terrorists who want to do us harm.”

Al-Maliki, a Shiite, has 30 days to do it, but the parties are under enormous pressure – from Americans and even Shiite religious leaders – to move quickly without the often intractable haggling over ministries.

The United States is hoping the new government will unify Iraq’s bitterly divided factions behind a program aimed at reining in both the Sunni-led insurgency and the Shiite-Sunni killings that escalated during months without a stable government.

Despite the violence, some Iraqis in Baghdad said they were encouraged by the legislators’ success in finally beginning to form a new government.

“It took too long, but it is a good step on the right direction. It could be a springboard for the stability of this country,” said Hussein Farij in Tahrir Square in central Baghdad.

“We pin a great hope on the formation of a new government. It must heal our country’s many wounds,” said Majeed Hameed.