ROME - An Italian hostage was executed by his Iraqi abductors, Foreign Minister Franco Frattini confirmed Wednesday night.

Earlier, the Arabic TV network Al-Jazeera reported the killing, saying it had received a video recording of the murder. The Italian ambassador to Qatar, where the network is based, watched the video and confirmed that the man killed was Fabrizio Quattrocchi, one of the kidnapped Italians, Frattini said.

Four Italian security guards were abducted Monday. The militants' videotape was accompanied by a statement from a previously unknown group calling itself the Green Battalion, which threatened to "kill the three remaining Italian hostages one after the other, if their demands are not met," Al-Jazeera said.

The group demanded the withdrawal of U.S. forces from Iraq, an apology from Prime Minister Silvio Berlusconi, and the release of religious clerics held in Iraq.

Meanwhile, Iraqi militants freed two aid workers and a journalist from Japan today, the Japanese foreign ministry said.

The three were handed over to the Japanese Embassy in Baghdad at 7:30 a.m., the ministry said in Tokyo. The three appeared unharmed.

The one-week crisis tested Prime Minister Junichiro Koizumi's commitment to the U.S.-led coalition in Iraq. The kidnappers threatened to kill the hostages if Japan did not withdraw a contingent of troops helping with reconstruction.

Koizumi refused that demand, saying he would not deal with terrorists and emphasizing that Japanese troops were in Iraq on a humanitarian mission.

Italy's Berlusconi has ruled out any withdrawal of troops and Frattini told the parliamentary commission that an Italian withdrawal would be "unimaginable." Pulling out Italy's 3,000 soldiers and paramilitary police from Iraq would mean "the victory of terrorism, civil war and defeat for the Iraqi people."

Dozens of foreigners have been taken hostage in recent days in Iraq, amid the most violent uprising since the end of major combat operations was announced in May.