Iraq's Interior Ministry has revoked the license of Blackwater USA, an American security firm whose contractors are blamed for a Sunday gunbattle in Baghdad that left eight civilians dead.

Sunday's firefight took place near Nusoor Square, an area that straddles the predominantly Sunni Arab neighborhoods of Mansour and Yarmouk.

In addition to the fatalities, 14 people were wounded, most of them civilians, the official said.

The ministry said the incident began around midday, when a convoy of sport utility vehicles came under fire from unidentified gunmen in the square.

The men in the SUVs, described by witnesses as Westerners, returned fire, and the witnesses said the vehicles are the kind used by Western security firms.

"We have revoked Blackwater's license to operate in Iraq. As of now they are not allowed to operate anywhere in the Republic of Iraq," Interior Ministry spokesman Brig. Gen. Abdul Kareem Khalaf said Monday. "The investigation is ongoing, and all those responsible for Sunday's killing will be referred to Iraqi justice."