Iraq's president openly praised Shiite (search) and Kurdish militias in a statement Wednesday that could further antagonize Sunni Arabs at a time of growing fears of sectarian strife.

Clashes in Baghdad (search) and other attacks around Iraq killed at least eight Iraqis as the Sunni-dominated insurgency pressed on with its campaign against the Shiite-led government. In addition, four U.S. troops were killed Tuesday and Wednesday.

Two U.S. soldiers were killed in an attack on their base in Tikrit (search), north of Baghdad, late Tuesday, while another was killed by a roadside bomb north of the capital, the military said. A fourth was killed Wednesday when a roadside bomb exploded near his vehicle close to Adwar, 10 miles south of Tikrit, the military said.

At least 1,680 U.S. military members have died since the war began in March 2003, according to an Associated Press count.

The wave of violence that broke out after the April 28 announcement of Iraq's new Shiite- and Kurdish-dominated government has killed more than 874 people, including more than 10 Sunni and Shiite clerics in apparent retaliatory slayings that raised fears the country was facing a civil war.

President Jalal Talabani's backing of the Shiite Badr Brigade militia came despite accusations by Sunni leaders that the militia has killed members of the minority. The Sunni leaders have demanded that it be disarmed and complained that it provides intelligence and support for some Shiite-dominated special security units.

The Badr Brigade was the military wing of the country's largest Shiite political party, the Supreme Council of the Islamic Republic in Iraq — or SCIRI. The party claims the Badr Brigade is no longer a militia but performs social and political functions.

"Badr is a patriotic group that works for Iraq's interest and it will not be dragged into sectarian or any other kind of conflict," said Abdul-Aziz al-Hakim, SCIRI's leader and the former commander of the Badr Brigade. "Badr is for all Iraqis," he added.

Talabani, himself a Sunni Kurd, spoke at a conference marking the second anniversary of the Badr Brigade's transformation from a solely military body to a political one.

"May those who describe the heroes of Badr and their Kurdish brothers as militia be doomed to failure," Talabani said.

"You and your (Kurdish) brothers are the heroes of liberating Iraq," he added. "You, my brothers, march on without paying attention to the enemies' claims because you and the (Kurdish militia) are faithful sons of this country."

There are no accurate figures on the size of the brigade, but it is thought to be smaller than the Kurdish Peshmerga militia, estimated at 100,000. The Peshmerga has been largely exempted from efforts to disband militias because of its close ties to the United States and its supporting role during the war.

Sunni criticism of Talabani's remarks was swift, with Abdul-Salam al-Qubeisi, spokesman of the influential Association of Muslim Scholars, saying the president was acting in line with "U.S. policies to prolong the struggle in Iraq and turn it into an Iraq-Iraq conflict."

Al-Qubeisi accused the Badr Brigade of providing intelligence to units such as the feared Wolf Brigade, an elite commando unit from the Interior Ministry that is headed by a top SCIRI member.

"We do not have problems with this party or another, we only have problems with the chasing and killing of Sunni clerics and their followers," al-Qubeisi said. "Even the militia elements who have joined the Iraqi army have been heavy-handed during army operations."

The Badr organization's leader, Hadi al-Amiri, challenged the association's head, Sheik Harith al-Dhari, to prove his group involvement in the killings and said an investigation should be held.

"If the accusations prove to be true, then we will apologize and punish the offenders, but if they turn out to be false, al-Dhari should apologize," he said at Wednesday's gathering.

On Tuesday, Laith Kuba, spokesman for Prime Minister Ibrahim al-Jaafari, a Shiite, said there was "no place for militias" in the new Iraq and that such forces could be incorporated into the police and army.

The complaints came a day after a Sunni Arab politician said two insurgent groups were willing to negotiate with the government, possibly opening a new political front.

Former electricity minister Ayham al-Samarie told The Associated Press the Islamic Army in Iraq and the Army of Mujahedeen — or holy warriors — were ready to open talks with the government aimed at eventually joining the political process. The groups account for a large part of the Sunni insurgents and were responsible for attacks that included assassinations and kidnappings.

A senior U.S. official confirmed that influential Sunni leaders have been negotiating with some insurgent groups interested in embracing the political process.

The official told reporters at a briefing that U.S. authorities have met with some of those leaders to try to persuade insurgents to lay down their arms.

"Some insurgents are irredeemable and have to be dealt with in a purely military way and there are some who are looking to enter the political process under some conditions," he said.

The official said he did not think those Sunni leaders who American authorities were talking to had a direct role in terrorist attacks, but they do have ties with insurgents.

The effort to begin talks comes at a delicate time for the government, criticized by Sunni Arab groups for deliberately targeting the minority in counterinsurgency campaigns such as the ongoing Operation Lightning in Baghdad.

The association said the operation, which has led to nearly 900 arrests, could spark sectarian strife. Now in its second week, the campaign involves thousands of Iraqi security forces and 7,000 U.S. troops, according to the U.S. military.

In Habaniyah, 50 miles west of Baghdad, insurgents attacked a supply convoy carrying supplies to a U.S. base, and local reporters said they saw at least seven bodies. U.S. military and diplomats said they were not aware of any Americans in the convoy.

Reporters who returned to the scene Wednesday saw four more bodies. The other bodies were still there and armed men were present.

Mbulelo Mtilwa of the South African Embassy in Jordan confirmed that a South African was part of the convoy but it wasn't known if he was killed, captured or wounded.

In other violence Wednesday:

—Gunmen killed two industry ministry officials in a drive-by shooting in the capital.

—One police officer was killed and six injured in clashes in northwest Baghdad.

—Police Col. Nashwan Hadi was killed in a drive-by shooting near his home in Mosul. The attackers then fired a rocket at his house, injuring five people, including two children.

—A police officer was shot and killed in eastern Mosul.

—A car bomb in Baqouba killed two people. Gunmen also killed a translator at an American base.