A delegation of Iraqi leaders is attempting to negotiate an end to fighting between coalition forces and insurgents in the Sunni stronghold of Fallujah.

At least one member of the Iraqi Governing Council and team of Iraqi leaders entered Fallujah Saturday to try to convince tribal and religious leaders there to hand over the people involved with the gruesome killing and mutilation of four American civilian contractors on March 31.

U.S. marines launched a major offensive operation against Fallujah earlier this week, cordoning off the city and allowing only women, children and elderly men to leave. Fierce clashes have erupted for the past six days, killing several hundred Iraqis and at least 40 U.S. troops.

Brigadier General Mark Kimmitt, the coalition's deputy director of operations, offered a cease-fire on Saturday, and called on armed fighters in Fallujah to join in.

"If the cease-fire holds, talks regarding the re-establishment of legitimate Iraqi authorities in Fallujah will begin," he said.

However, military officials said one marine was killed and one Iraqi wounded after the cease-fire was called. They said enemy combatants also fired on a convoy carrying humanitarian supplies.

Elsewhere in Iraq, U.S. Army officials said 12 insurgents were killed in the northern city of Al-Thubat Saturday.

Fighting between Shiite militias and coalition forces in southern Iraq came to a pause Saturday, after a representative from the radical cleric Moqtada al-Sadr declared a cease-fire through the religious holiday of Al-Arbaeen, which ends Sunday.

Meantime, Iraqi fighters in different parts of the country claim to have taken a number of foreigners hostage, including two Germans, one Briton, and three Japanese.

Tokyo's foreign minister appealed Saturday for the Japanese hostages to be released. Their captors threatened to burn the hostages alive by Sunday, if Japanese troops do not withdraw from Iraq. The Japanese prime minister, Junichiro Koizumi, has pledged not to give in to the terrorists' demands.

Italy's prime minister, Silvio Berlusconi, made a surprise visit Saturday to Italian troops based in the southern Iraqi city of Nasiriyah, where 19 soldiers were killed in a suicide attack last November.