US troops massed on the outskirts of Iraqi southern city of Najaf on Tuesday, ready for a possible operation against the militiamen led by Shi'ite Muslim cleric Muqtada al-Sadr.

A Sadr-led insurgency aimed at ending the occupation of US-led coalition forces has swept the Shi'ite Muslim areas in Baghdad and southern Iraq since the end of last month.

US President George W. Bush Tuesday called on Sadr to disband his militia while US commanders vowed to kill or capture him. Sadr said earlier he was willing to die for his campaign to end the US-led occupation, but also said he was in talks to end the uprising.

Meanwhile, fresh clashes between US Marines and Sunni insurgents on the eastern edge of Fallujah, west of Baghdad, threatened a truce in the city. Twenty insurgents attacked a Marine position in a residential neighborhood and a fierce battle followed to extract the vehicle which came to support the position.

The deadly clashes, which flared up last Monday after four American civilians were killed and mutilated in Fallujah, have left over 600 Iraqis and 60 US soldiers killed.

The bloody upsurge also led to a spate of kidnappings. US State Department official said Tuesday that four bodies have been found in Iraq amid reports that two US soldiers and seven US civilians are missing.

There are also reports saying that over 60 foreigners, including Americans, Japanese, Italians, Germans, have been abducted.

Also on Tuesday, a US helicopter was shot down near Fallujah and a Marine team that came to secure was ambushed and suffered casualties.

But US President Bush said at a rare press conference Tuesday the United States will send more troops to Iraq and will stay the course there.

Source: Xinhua