U.S. command in Ramadi said four Marines were killed in an ambush in the last 24 hours, but was unable to confirm that the bodies shown in the videotape are those of the dead Marines, reports CBS News Correspondent Charles D'Agata.
Elsewhere, a roadside bomb exploded near the northern city of Mosul, killing four Iraqis and wounding four others. The military said the Iraqis were employed by a private company working in northern Iraq, though it didn't say which one.
On Sunday, attackers lying in wait for Iraqi troops detonated a roadside bomb on the dangerous road leading to Baghdad's airport Sunday, killing two Iraqi soldiers and wounding 11. American troops took the Iraqi wounded to a U.S. aid station and waited while they were treated.
A mortar round also injured six police and four Iraqis in a separate attack Sunday near the Iraqi central bank in Baghdad.
An American Marine was killed in a non-combat incident Saturday in Anbar province, which includes Ramadi and Fallujah, the U.S. military said Monday.
Meanwhile, a video delivered by terrorists to Arab television threatened to behead a South Korean worker kidnapped in Iraq, and a report surfaced that the same kidnappers may be holding as many as 10 other foreigners captive.
In other developments:
Allawi also said he intends to resurrect aspects of Iraq's former military, enlarging the overall army while creating police and paramilitary units focused on controlling riots and fighting guerrillas.
"They are trying to destroy our country and we are not going to allow this," Allawi said Sunday.
He added that Coalition Provisional Authority chief L. Paul Bremer's May 2003 decision to disband the Iraqi army was a mistake. The fledgling army being trained by the United States is coming under attack as Allawi's interim government prepares for the handover of sovereignty.
"We might impose some kind of martial law in some places if necessary in accordance with the law and in respect to the human rights and the international law," he said.
Sen. Joseph Biden, the top Democrat on the Senate Foreign Relations Committee, expressed concern over the idea, saying Iraqi troops were not strong enough to enforce it and that U.S. forces could be dragged into doing so.
"I'm not so crazy about this," Biden said on ABC.
"A government should never lay down an order they can't enforce. I am positive that Allawi is not in a position to enforce such a law now, without the United States doing it," he said.
The incoming government is also considering an amnesty for Iraqi guerrillas who haven't taken direct roles in killings of U.S.-led occupation forces or Iraqis, Interior Minister Falah Hassan al-Naqib told reporters, offering few details.
In the videotape aired Sunday on the Arab satellite TV network Al-Jazeera, the kidnappers identify themselves as belonging to a group led by Zarqawi, a Jordanian-born terrorist who is linked to al Qaeda.
South Korean hostage Kim Sun-il, 33, was kidnapped June 17th near Fallujah and has been identified as the man in the terrorist-released video who is heard pleading for his life, and imploring South Korea to withdraw its troops.
In the tape he screams in English, flailing his arms: "Please, get out of here," apparently referring to South Korean troops in Iraq, "I don't want to die. I don't want to die. I know that your life is important, but my life is important."
On the videotape, the plea from Kim Sun-il is followed by scenes of him kneeling in front of three masked men, one of them armed with a Kalashnikov rifle. The man standing in the middle read a statement in Arabic:
"Our message to the South Korean government and the Korean people: We first demand you withdraw your forces from our lands and not send more of your forces to this land. Otherwise, we will send to you the head of this Korean, and we will follow it by the heads of your other soldiers."
The South Korean government, after an emergency cabinet meeting, announced that it will not withdraw the troops now in Iraq, and will keep its promise to send 3,000 more - making it the third largest contributor of troops there, after the U.S. and Britain.
Yonhap news agency reports that the other foreign captives include a European journalist and "third country" employees for the U.S.-based contractor Kellogg Brown and Root. Sun-il also worked for a contractor.
The threat against the South Korean hostage surfaced as authorities in Saudi Arabia continue to search for the body of, beheaded on Friday in Saudi Arabia by terrorists linked to al Qaeda.