Gunmen killed the head of a regional office of one of Iraq's largest Shiite parties in a drive-by shooting south of the capital, police and officials said Wednesday.

Ali al-Khalisi (search), the head of Diyala province for the Supreme Council of the Islamic Revolution in Iraq (search ), was gunned down in the town of Mahmoudiya, about 25 miles south of Baghdad, said Haitham al-Husseini, a SCIRI spokesman.

Gunmen drove up beside his car and opened fire, said Alaa Hussein from Mahmoudiya police, and Dawoud al-Taei, from the hospital that received al-Khalisi.

Al-Khalisi was in Mahmoudiya visiting family, al-Husseini said. He blamed Saddam loyalists and insurgents for the killing.

"It must be terror gangs who try to halt the political process in this country," al-Husseini said. "Remnants of the former regime and extremists have set out to exterminate political figures who work for this country's interest."

Al-Khalisi also headed SCIRI's militia in the Diyala province, known as the Badr Brigade (search ), an anti-Saddam group. Run by former Governing Council member Abdel Aziz al-Hakim, SCIRI maintains close ties to Iran.

Last month Abd el-Oun Hassan, the head of SCIRI's Musayyib office, was gunned down by militants.