Iraqi security forces stormed a house in this Shiite Muslim holy city early Wednesday, leaving one suspected terrorist and one policeman dead, police said.

The shootout came after an explosion Sunday in Najaf's (search) city center left 54 people dead and 142 wounded. Authorities said Monday that they detained some 50 suspects, including a citizen of an Arab country.

Police said they detained another four suspected militants Wednesday after they stormed their hideout. The four are Wahabis (search), or followers of an austere brand of Sunni Islam practiced mostly in Saudi Arabia.

Wahabis are suspected of having influence over militants waging a 17-month insurgency in (search)to oust coalition forces and destabilize the U.S.-backed interim authorities.