The U.S. military said Sunday that the bodies of two American pilots killed when their Apache helicopter crashed near Baghdad were recovered and the aircraft was probably shot down. Three other U.S. soldiers were reported killed in Baghdad and northern Iraq.

The AH-64D Apache Longbow went down about 5:30 p.m. Saturday during combat operations west of Youssifiyah, about 10 miles southwest of Baghdad, the U.S. command said in a statement.

"The soldiers' remains were recovered following aircraft recovery operations at the crash site" of the helicopter "which went down due to possible hostile fire," the statement said.

In political developments, Secretary of State Condoleezza Rice and British Foreign Secretary Jack Straw made a surprise visit to press Iraqi politicians to speed up the formation of the government. The trip came as Prime Minister Ibrahim al-Jaafari faced mounting pressure from his fellow Shiites to withdraw his nomination for a second term.

No further details were released on the helicopter crash, but Youssifiyah is located in the "triangle of death," a religiously mixed area notorious for attacks by Sunni extremists against Shiites traveling between Baghdad and religious shrines south of the capital.

It was the first loss of a U.S. helicopter since three of them crashed in a 10-day period in January, killing a total of 18 American military personnel. At least two of those helicopters were shot down.

The U.S. command also said three more soldiers had been killed — two by a roadside bomb late Saturday in central Baghdad and another from non-hostile related injuries suffered near the northern city of Kirkuk.

The five U.S. deaths brought to at least 2,333 the number of American service members killed since the Iraq war started in March 2003, according to an Associated Press count.

In Ramadi, an insurgent stronghold 70 miles west of Baghdad, a roadside bomb exploded Sunday near a U.S. convoy, blowing parts of a vehicle onto the roof of a nearby building. No U.S. casualties were reported, but witnesses said men danced around the wreckage, chanting "God is great."

The latest U.S. casualties followed one of the least deadly months of the Iraq war for American forces. Thirty-one American service members died during March, the lowest monthly death toll for the U.S. military since February 2004.

However, about 400 Iraqis died, many in violence between Shiite and Sunni Muslims that escalated following the Feb. 22 bombing of a Shiite shrine in Samarra that triggered a wave of reprisal attacks against Sunni mosques and clerics.

The rise in sectarian violence has added new urgency to the need to form a government of national unity following the Dec. 15 national elections to prevent the country from disintegrating into chaos.

Underscoring the problem, the bodies of at least 42 men — handcuffed and shot in the head or chest — were found over the weekend in several neighborhoods of the Iraqi capital, police Maj. Falah al-Mohammedawi said Sunday.

However, talks among the Shiite, Sunni and Kurdish parties have bogged down due to wide differences among the sectarian and ethnic groups.

Sunni and Kurdish politicians blame much of the impasse on the decision by the dominant Shiite bloc to nominate al-Jaafari for a second term. Critics maintain al-Jaafari was ineffective in combatting the Sunni led-insurgency and curbing sectarian tensions.

Rice was careful to say the U.S. did not want to interfere in the democratic process, but she harped on al-Jaafari's failure to organize a unity government.

Shiite legislator Jalal Eddin al-Sagheer also said Sunday that the prime minister no longer had the acceptance of Iraqi parties and the international community and should step aside.

"There is no other way out of the government formation problem," said al-Sagheer, a member of the United Iraqi Alliance and of SCIRI, the largest Shiite political organization. Further delays could "lead to more bloodshed," he added.

Qassim Dawoud, who on Saturday became the first Shiite politician to publicly call for al-Jaafari to step aside, warned of "a political and security vacuum."

"Calling for the withdrawal of al-Jaafari is the only way to find an exit to the crisis," he told the Al-Arabiya network on Sunday.

Shiite politicians get first crack at the prime minister's job because they are the largest bloc in parliament.

U.S. officials have made little effort to conceal their desire that al-Jaafari leave office because of his close ties and strong backing from radical Shiite cleric Muqtada al-Sadr.

A week ago, Shiite officials said U.S. Ambassador Zalmay Khalilzad brought a letter from President Bush objecting to a second term for al-Jaafari to a meeting with the Abdul-Aziz al-Hakim, leader of the Supreme Council for the Islamic Revolution in Iraq.

But al-Jaafari, a physician who spent years in exile in Iran and Britain, has refused to step aside. He won the nomination in a ballot among Shiite legislators in February, beating al-Hakim by one vote because of al-Sadr's support.

Shiite officials say they fear that a bid to replace al-Jaafari could lead to the collapse of their alliance.

In other developments:

— The Iraqi joint command center in Baqouba said assailants blew up a small Shiite mosque Sunday in the region, some 35 miles northeast of Baghdad. However, a U.S. spokesman in Baghdad, Maj. Tim Keefe, disputed the report, saying American troops went to the reported location and "were unable to find any mosque that had been damaged."

— Sunni sheik Abdul-Minaam Awad was assassinated in a village 40 miles west of Baghdad, a Sunni clerical association reported.

— Prominent Sunni lawmaker Saleh al-Mutlaq said his brother, Taha, disappeared while driving north of Baghdad last week in a possible kidnapping.

— Six insurgents were killed Sunday when a homemade bomb they were building exploded inside a house in Madain, police said.