An audio tape posted Friday on the Internet purportedly from al-Qaida ally in Iraq Abu Musab al-Zarqawi called for more attacks on US forces.

The speaker in the tape, who identified himself as Zarqawi, urged "the sons of the Islamic nation" to "stand firm" against the US forces and "turn their days into nights."

"We promise God that (US President George W.) Bush will not enjoy peace of mind and that the US forces will not have a good life as long as our hearts are beating," the speaker added. 

The authenticity of the tape, posted on a website frequently used by Islamic militants, can not be verified yet. 

Zarqawi, the Jordanian born al-Qaida ally and most wanted man in Iraq with a US bounty of 25 million dollars on his head, is believed to have masterminded some of the most violent and gruesome attacks on US and Iraqi forces.

The tape attributed to Zarqawi surfaced as Iraq witnessed a spate of insurgent attacks on Friday. At least nine car bombs hit security forces in Baghdad and Madain, a town south of the capitalcity, killing some 20 and wounding over 60 others.

Source: Xinhua