Gunmen killed a senior official in Iraq's largest Shiite political party Monday in a drive-by shooting in Baghdad, a party aide said.

Shahir Faisal Shahir (search) was shot while traveling to his office, said Haitham al-Hissaini, a top party adviser for the Supreme Council of the Islamic Revolution (search) in Iraq.

Shahir carried the rank of major general in the party's militia, which is known as the Badr Brigade. The militia fought the former regime of Saddam Hussein (search).

The Supreme Council of the Islamic Revolution in Iraq is the country's biggest Shiite party and maintains close ties to Iran. It is headed by Abdel-Aziz al-Hakim.

The shooting took place only hours before Iraq's prime minister designate, Iyad Allawi (search), announced that nine major political parties had agreed to disband their militias in a move to assert state control before the return of sovereignty June 30.

Allawi said the Badr Brigade of the Supreme Council of the Islamic Revolution in Iraq also signed on to the deal, although representatives of the party claimed negotiations to disband had not yet begun.

Under the plan, the militias would disband with many of their members taking jobs in the state police or security services. Most of the militias are controlled by mainstream political movements represented in Iraq's new interim government.