BAGHDAD, Iraq – Terrorists beheaded three hostages said to be Iraqi Kurd militiamen, showing their deaths in a video posted on a Web site yesterday and denouncing Kurdish political parties for cooperating with Americans in Iraq.

In a separate incident, a group claimed to have kidnapped 18 members of the Iraqi National Guard, according to the Arabic station Al Jazeera, which said the soldiers were threatened with death unless a detained Shiite leader is freed within 48 hours.

The bodies of the three slain hostages were found by a road outside the northern city of Mosul, said Sarkawt Hassan, security chief in the mainly Kurdish town of Sulaimaniyah. He identified them as members of the peshmerga terror group of the Kurdistan Democratic Party.

“They beheaded them,” Mr. Hassan said.

Prime Minister Allawi vowed his government was working for the release of all hostages, including two Americans and a Briton who are also threatened with decapitation. Their captors claim to be from an Al Qaeda-linked terrorist group.

News of another kidnapping emerged yesterday, as the Lebanese Foreign Ministry said three Lebanese working for a travel agent and their Iraqi driver were snatched on the highway between Baghdad and the insurgency stronghold of Fallujah. The captives were identified as Fadi Munir Yassin, Cherbal Karam Haj, and Aram Nalbandian, all Lebanese, and Iraqi Ahmed Mirza.

The hostages’ beheading was claimed by the Ansar al-Sunna Army, a group that has targeted Iraqi Kurds and that previously killed 12 kidnapped Nepalese workers.

A statement from the group, posted with yesterday’s video, said the three were abducted as they were transporting military vehicles to a base in Taji, 15 miles north of Baghdad.

The video shows three young men, two of whom hold up identity cards. Seconds later, each has his throat slit. A man is seen cutting off each hostage’s head. The heads are then seen placed on the backs of the victims.

The “apostate military men, affiliated with the traitor Kurdistan Democratic Party,” were beheaded after being interrogated, the statement said. Their bodies were left on the road “for them to be an example to others, and for us to avenge our women, children and elderly who die daily from American raids.”

The statement’s authenticity could not be immediately verified.

It said Ansar al-Sunna Army has targeted Iraqi Kurdish parties because they have “sworn allegiance to the crusaders and fought and are still fighting Islam and its people.” It accused the groups of protecting American forces.

The statement also accused the leaders of Iraq’s two main Kurdish parties, Massoud Barzani and Jalal Talabani, of being servants of Israel.

The 18 National Guard troops were taken by a group calling itself Brigades of Mohammed bin Abdullah, according to the Al Jazeera report.

A brief video clip aired by the station showed men in military dress sitting on the floor, with men standing behind them pointing guns to their heads. Most of the hostages had their heads bowed, but they were not blindfolded and appeared uninjured.

No audio was aired, but Al Jazeera’s announcer said the terrorists threatened to kill the 18 unless Hazem al-A’araji, a member of rebel Shiite cleric Muqtada al-Sadr’s office in Baghdad, was released within 48 hours.

American forces and soldiers from Iraq’s national guard raided the Baghdad houses of Mr. al-A’araji and another senior aide to Mr. al-Sadr, Raed al-Khadumi, on Saturday. Mr. al-A’araji and his brother were detained.

Abu Dhar al-Kanani, spokesman for Mr. al-Sadr’s Mahdi Army militia in Baghdad, told Al Jazeera that the terror group had nothing to do with the soldiers’ abduction.

The Ansar al-Sunna Army has been accused in a number of attacks on American and Iraqi forces and on Kurds – including February 1 bombings against Kurdish political offices in the northern city of Irbil that killed 109 people.