US-led forces conducting a crackdown on al-Qaida killed a senior member of the insurgent group who was responsible for the high-profile kidnappings of several Westerners, a military spokesman said today.

An American hostage who was kidnapped in Iraq last year with Briton Norman Kember has been killed.

An extremist group posted a video on a website today showing a man it said was an American hostage being shot in the back of the head, and the German government said one of its citizens released by kidnappers was expected to leave Iraq.

Kidnappers holding four Westerners made no contact with Iraqi authorities today, the day which they had set as a deadline to kill the humanitarian activists unless US and Iraqi authorities release all prisoners they hold in Iraq, the interior ministry said.

US AND Iraqi troops launched an operation in western Iraq yesterday to clear insurgents from a suspected safe area used to make car and roadside bombs.