US warplanes bombed targets near the house of radical Shiite cleric Moqtada al-Sadr in the holy city of Najaf on Thursday as US marines battled militiamen in the area, Qatar-based al-Jazeera reported.

Plumes of black smoke rose from the area as the fighters from each sides traded heavy fire. There was no immediate word on whether the cleric was at the house.

US forces launched an major offensive in Najaf, 160 km south of Baghdad, to end a week-long insurgency in the city. Sadr had asked his militiamen earlier this week to fight on even if he was killed or captured.