(AFP) - The spiritual leader of Iraqi Shiites, who are set to dominate the new government, on Sunday demanded a major say for Islam in lawmaking as the abduction of four Egyptians heightened fears for foreigners.

Amidst new insurgent violence that left at least 10 dead, Grand Ayatollah Ali al-Sistani and another top Shiite cleric staked out a radical demand that the constitution must refer to Islam as the sole source of legislation.

Sistani is also the guiding light of the United Iraqi Alliance, the coalition of Shiite parties that leads in the vote count after Iraq's historic January 30 election.

The new national assembly is to oversee the writing of a new constitution and the role of Islam has been at the heart of months of debate between rival parties and factions as well as by US officials.

A surprise statement released by Sheikh Ibrahim Ibrahimi, a representative of Grand Ayatollah Mohammad Ishaq al-Fayad, one of the five key marja, or Shiite religious leaders, set out the demand.

"All of the ulema (clergy) and marja, and the majority of the Iraqi people, want the national assembly to make Islam the source of legislation in the permanent constitution and to reject any law that is contrary to Islam," said the statement.

A source close to Sistani announced soon after that the spiritual leader backed the demand.

"The marja has priorities concerning the formation of the government and the constitution. It wants the source of legislation to be Islam," said the source.

The influence of Islam was a sticking point when an interim constitution was drawn up last year under the US-led occupation.

After often acrimonious debate and a veto threat by US administrator Paul Bremer, the final version said Islam should be "a source" of legislation rather than the sole source.

The US administration reacted cautiously to the ayatollahs' demand.

In Washington, US Vice President Dick Cheney said Iraqis would decide their future.

"They will do it in accordance with their culture and their history and their beliefs and whatever role they decide they want to have for religion in their society. And that's as it should be," he told Fox News television.

Meanwhile foreigners in Iraq were again put on their guard by the kidnapping of four Egyptian telecoms engineers in front of their Baghdad house.

It came only two days after an Italian reporter was abducted in the centre of the capital.

The engineers worked for a subsidiary of the Egyptian telecom firm Orascom, which runs the main mobile phone network in the Baghdad area.

Two groups have claimed responsibility for the kidnapping of Italian reporter Giuliana Sgrena.

One previously unknown Islamist group, the Organisation for Jihad in the Countries of Mesopotamia, said the 56-year-old correspondent would be killed unless Italy announces by Monday night that it would withdraw its 3,000 troops in Iraq.

The same demand was made by another group, the Organisation of Islamic Jihad, which claimed responsibility in an Internet statement on Friday.

There was no confirmation of the authenticity of either claim.

French reporter Florence Aubenas was abducted with her translator in Baghdad one month ago and there has been no news of her fate.

Insurgents have not eased up their renewed bloody campaign, despite a brief lull after the election.

At least 10 people were reported dead Sunday as Iraqi security forces clashed with rebels in volatile Sunni Muslim districts north of Baghdad and the so-called Triangle of Death, officials said.

More than 25 Iraqi civilians and security forces were killed on Saturday alone, and a US marine also died during what the US military called "security operations" south of Baghdad.

The militant Ansar al-Sunna group, which is linked to Al-Qaeda, said Saturday that it had executed seven Iraqi soldiers who were captured following an ambush west of Baghdad last week.

Election commission workers kept up the count from the first free vote in more than 50 years vote but no figures have been released since Friday.

With 3.3 million votes counted out of an estimated eight million cast, the main Shiite coalition backed by Grand Ayatollah Ali al-Sistani held a commanding lead.

Most major Sunni parties called for a boycott of the vote and leading Sunni clerics on Saturday demanded a timetable for the withdrawal of US-led foreign troops to join talks on a new constitution.

The Committee of Muslim Scholars, Iraq's leading Sunni religious authority, said that if a timetable was established it would urge insurgents to end the country's bloodshed.

Cheney told Fox that the United States would not stay in Iraq "a day longer than necessary" but would not pull its troops out until the mission had been completed.

Tensions over the vote, meanwhile, are also on the rise in the ethnically divided northern city of Kirkuk.

Turkmen and Arab parties are accusing Kurdish parties of fixing the election for the provincial council, which was also held January 30, and stepping up moves to have Kirkuk attached to the autonomous Kurdish region of northern Iraq.