Abu Musab al-Zarqawi, a Jordanian accused by U.S. officials of organising many deadly attacks in Iraq, made the threat against Prime Minister Iyad Allawi on an Islamist website.

"As for you, Allawi -- sorry, the democratically elected prime minister -- we have found for you a useful poison and a sure sword," said a taped voice, purported to be Zarqawi's own.

Allawi, a tough former Baathist who plotted against Saddam Hussein from exile, responded defiantly.

"We do not care about these threats, we will continue to rebuild Iraq and work for freedom, democracy, justice and peace. Iraqis have faced these threats before," said a spokesman from his office.

The interim government, selected by a U.N. envoy in consultation with U.S. and Iraqi officials, will be sworn in when the U.S.-led occupation formally ends in a week's time.

Zarqawi's group, Jama'at al-Tawhid and Jihad, said on Tuesday it had decapitated South Korean hostage Kim Sun-il after Seoul refused to withdraw forces from Iraq.

Hours after finding Kim's body, U.S. forces launched an air strike on a suspected safe house of Zarqawi's group in Falluja, west of Baghdad, the second such raid in four days. Residents said the attack destroyed a garage and killed four people.

Arabic Al Jazeera television showed footage on Tuesday of hooded gunmen standing over a kneeling Kim, who was blindfolded and wearing an orange tunic similar to those worn by prisoners in U.S. detention facilities such as Guantanamo Bay.

US STRIKE

The US military said it launched a "precision strike" on a safe house used by militants linked to al Qaeda operative Abu Musab al-Zarqawi in the Iraqi city of Falluja on Tuesday night.

But witnesses and a hospital official said the strike hit a garage,

killing 20 civilians and wounding six other people in Iraq's most rebellious town.

(Reuters and AFP)