A Shiite Muslim cleric threatened on Friday to launch homicide attacks if U.S. troops attack him and his forces in the holy city of Najaf.

Muqtada al-Sadr (search), was speaking during the Friday prayers sermon in Kufa, another Shiite Muslim holy city few miles from Najaf. The area is mostly controlled by his Al-Mahdi Army (search) militia, whose members have clashed with U.S. troops several times since their uprising began on April 4.

"Some of the Mujahideen brothers have told me they want to carry out martyrdom attacks but I am postponing this," al-Sadr said in front of thousands of worshippers. "When we are forced to do so and when our city and holy sites are attacked, we will all be timebombs in the face of the enemy."

He condemned homicide bombings Wednesday in the southern city of Basra that killed 73 people because they targeted Iraqi police and civilians.

U.S. forces are deployed outside Najaf, but their mission to capture or kill al-Sadr has effectively been put on hold while negotiators try to resolve the standoff. U.S. commanders say they have no intention for the time being of entering Najaf (search), the holiest Shiite city.

Al-Sadr is wanted in the April 2003 killing of a rival cleric.