Iraqi authorities have banned an American security firm under contract to the U.S. government after some of its employees were implicated in a Baghdad firefight that left eight civilians dead.

CNN reports that Iraq's Interior Ministry revoked the license of Blackwater USA on Monday, a day after the gun battle near Nusoor Square that also wounded 14 people, most of them civilians, an Iraqi government official said.

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

Blackwater is one of several security firms that the U.S. government has hired to protect diplomats, reconstruction workers, and government officials. About 25,000 employees of private security firms work in Iraq, according to U.S. congressional reports. The government has spent about $4 billion for their services, a Congressional committee has estimated.

Dozens of these workers, many of them U.S. veterans, have been killed in Iraq. In a memorably grim event, four Blackwater employees were killed in Falluja in 2004 and their bodies were dragged through the streets of that city west of Baghdad, hanged from a bridge, and set on fire.

Iraqi authorities have complained about shootings by private military contractors in the past, but Iraqi courts do not have jurisdiction over them, the Congressional Research Service said.

The decision to eject Blackwater, which is based in Mayock, North Carolina, came a week after an independent commission headed by General James Jones, the former top U.S. commander in Europe, said that the Iraqi Interior Ministry was corrupt and ineffective.

The Jones Commission recommended that the Interior Ministry completely disband the Iraqi National Police force, saying many ordinary Iraqis see it as dominated by Shias and "operationally ineffective."

On its web site, Blackwater says it was founded in 1997 by a former U.S. Navy SEAL. It describes itself as "a professional military, law enforcement, security, peacekeeping, and stability operations firm."

It adds that "Blackwater USA consists of nine separate business units: Blackwater Training Center (the largest private firearms and tactical training center in the U.S.), Blackwater Target Systems, Blackwater Security Consulting, Blackwater Canine, Maritime Security, manufacturing of custom Armored Vehicles, Parachute Jump Team, Aviation, and Raven Development Group."