Iraq's central holy city of Najaf, where supporters of radical Shiite cleric Moqtada al-Sadr are holed up, was pounded by US aircraft on Friday, Qatar-based al-Jazeera TV channel reported.

As fierce clashes continue between Sadr's supporters and US troops. the US planes pounded the city after midnight and early Friday morning, the channel said.

The battles concentrated around the 20th Revolution Square and Najaf vast cemetery, it said.

The streets of the city were empty as people were forced to stay at home while the power and telephone communication lines were cut, al-Jazeera added.