Defiant Shia in Baghdad military parade

Shia cleric Moqtada Sadr, whose Mehdi Army fought US troops during the occupation, has rallied followers for a military parade across Iraq.

It comes as Islamist-led militants and pro-government forces continue to engage in fierce battles for the Baiji oil refinery and Tal Afar airport in northern Iraq.

Baiji, Iraq's biggest refinery, is surrounded by the rebels, who say they have seized most of Tal Afar airport.

The US said it would send some 300 military advisers to help the fight against the insurgents.

President Barack Obama stressed that US troops would not fight in Iraq.

Jonathan Beale reports from Baghdad.