The firebrand Iraqi cleric whose followers make up a crucial swing vote said Sunday the prime minister must resign as a first step to pull Iraq out of the morass that has all but paralyzed its government.

Speaking to reporters from his headquarters in the holy Shiite city of Najaf, cleric Muqtada al-Sadr said he would not bow to pressure from Iran and other Shiite religious leaders to continue supporting Prime Minister Nouri al-Maliki. He joins Sunni and Kurdish officials who seek to oust al-Maliki, a Shiite, in the first major Shiite defection against the premier.

Al-Sadr accused al-Maliki's government of keeping Iraq's minorities away from power and failing to fix legal systems and other public services. He said he would direct his party's 40 lawmakers to support a no-confidence vote against al-Maliki if he is sure other political blocs in parliament will provide the rest of the 163 votes needed.