Three of the soldiers were killed in a roadside bombing late on Friday near Tuz, 150km north of Baghdad, the military said on Sunday. Another soldier was wounded in the blast and evacuated.

One soldier on patrol was killed on Sunday and three others were wounded in a blast east of Rutbah, 400km west of Baghdad, the military said. In another roadside bombing, one soldier was killed on Saturday and another wounded in western Baghdad.

On Friday, a US commander said the number of roadside bomb attacks against American convoys in Iraq had doubled in the past year to about 30 a week. Dozens of bombings, usually detonated by remote control, target US and Iraqi patrols each day.

The military said in a brief statement from Baghdad that one soldier was found dead on Friday of a gunshot wound. The military said an investigation was under way and did not say where the soldier was found or if an attack was suspected in the soldier's death.

Al-Zarqawi aide killed

Also on Sunday, the US military said a lieutenant of al-Qaida's chief in Iraq, Abu Musab al-Zarqawi, was killed by Iraqi security forces in Mosul.

"He was also suspected of resourcing and facilitating suicide bomber attacks against coalition, Iraqi security forces and Iraqi citizens throughout the country"

US statement on Abu Zubair

Muhammad Salah Sultan, also known as Abu Zubair, was killed on Friday, the US statement said.

The statement said Abu Zubair was a "known member of al-Qaida in Iraq" and an al-Zarqawi lieutenant who was sought for his role in a July suicide bombing of a police station in Mosul in which five Iraqi police were killed.

Abu Zubair was wearing an explosives pack when he was killed, the statement said.

"He was also suspected of resourcing and facilitating suicide bomber attacks against coalition, Iraqi security forces and Iraqi citizens throughout the country," the statement said.

The statement added that last week, US and Iraqi forces captured three bomb makers and six foreign fighters as well as finding and clearing 101 improvised explosive devices in the Mosul area.

Mass grave

The bodies of 30 people, including two women, were discovered in a mass grave south of Baghdad on Sunday, and police have made several arrests in connection with the finding, security sources said.

"A grave containing 30 mutilated bodies, of which two were women, was discovered at Awerij," about 20km south of the Iraqi capital, said police lieutenant Muthanna al-Shumari.

Al-Shumari said the grave, in Babylon province whose capital is Hilla, dated back about six months.

Beheaded body

In the capital, the beheaded body of an unidentified woman was found on Sunday in the violent southern neighbourhood of Dora, police 1st Lieutenant Thaer Mahmoud said.

"If the Sunnis refuse to accept the agreements, we will present the draft[constitution] as it is to the National Assembly"

Mahmoud Othman,
Kurdish parliamentarian

In northeast Baghdad, four police officers on a patrol were wounded by a roadside bombing late on Saturday, police Captain Nabil Abdul Qadir said.

Another bomb along a highway killed one civilian on Sunday and injured another in Mahmoudiya, about 30km south of Baghdad, police Captain Saad al-Samaraei said.

Police also said two women were injured early on Sunday when a mortar fell at the Noor Hospital in northwest Baghdad.

The violence came one day after American and UN diplomats stepped up pressure on Sunni Arabs to accept a new constitution that is due to be presented to parliament on Monday. 

Sunni unease

A top Sunni official said his group would never accept terms that they fear would lead to the division of the country.

Sunni Arabs were to meet on Sunday with members of former prime minister Iyad Allawi's secular party and the Shia would confer with Kurds, Iraqi officials said, adding that US Ambassador Zalmay Khalilzad was expected to attend both sessions.

A parliament session scheduled for Sunday was postponed because many legislators were working on the constitution, said Aref Tayfour, the deputy speaker of the assembly.

President Jalal Talabani -who had earlier ordered the release of all female detainees held by Iraqi security forces- predicted that a draft constitution would be ready by the deadline, and a Kurdish official said the draft would be presented to parliament with or without Sunni approval.

Sunni leaders said they would not bow to pressure.

No to federalism

"We will not be subdued and will continue to cling to our stance," Sunni negotiator Kamal Hamdoun said on Saturday.

"We don't accept federalism ... We don't want federalism. We are confident that federalism means division and federalism cannot be approved at this time."

Sunni groups have expressed
unease with the charter blueprint

Mahmoud Othman, a Kurdish parliamentarian and member of the committee drafting the constitution, said the Shia and Kurds had reached a number of agreements and were working to persuade the Sunnis to join them.

Othman said on Saturday that "if the Sunnis refuse to accept the agreements, we will present the draft as it is to the National Assembly".

Political pressures

Hamdoun, the Sunni leader, said his group did not consider itself bound by an agreement worked out between the Shia and Kurds. He said the Sunni Arabs were under "Iraqi and non-Iraqi pressure" but "we are not affected by pressure".

That strategy could backfire, however, in the 15 October  referendum when voters will be asked to ratify the constitution. According to the country's interim charter, the constitution will be void if it is rejected by two-thirds of voters in three of the 18 provinces. Sunni Arabs are a majority in four.

The US considers the charter a key part of the process to curb a Sunni-dominated insurgency. In his weekly radio address, US President George Bush said that the Iraqi constitution "is a critical step on the path to Iraqi self-reliance".

Talabani told reporters that negotiations were concentrating on the federalism question and the role of Islam in the government.

Unresolved tensions

"We have gone forward," Talabani said on Saturday. "There is a meeting today and another meeting tomorrow, and God willing we will finish the job tomorrow."

Negotiations were thrown into a tailspin on Thursday when the leader of the biggest Shia party, Abdul-Aziz al-Hakim, called for a Shia autonomous government in central and southern Iraq, including the southern oil fields.

The demand was rejected by Sunni Arab delegates
.