Baghdad  - A commander of a tribal police unit, who was formerly a senior member of the al-Qaeda terrorist network in Iraq, was wounded along with three policemen in a suicide bombing Thursday in northern Iraq, according to police.

A suicide bomber wearing an explosive belt attacked the motorcade of the police chief of Duluiyah and his companions, including Mullah Nazim al-Juburi, the commander of the local Awakening Council, police sources told the Voices of Iraq news agency.

Al-Juburi was lightly injured in the attack, which occurred in Duluiyah in the northern Salah al-Din province.

The Awakening Councils are US-backed tribal forces formed in Sunni areas to fight insurgents of Sunni extremist groups, such as al-Qaeda in Iraq.

Al-Juburi, who is now the imam of the main mosque in Duluiyah, was himself a leader of the al-Qaeda in Iraq group for the past four years until he turned against it and set up the local Awakening Council.

He has survived many assassination attempts and been involved in clashes with al-Qaeda gunmen.

Also in Salah al-Din, tribal policemen killed four insurgents and found a weapon cache in Tikrit, 175 kilometres north of Baghdad, the US military said Thursday.

"Several suicide vests were discovered along with 800 pounds of homemade explosives and other material to produce improvised explosive devices," the military said. (dpa)