Militants loyal to Jordanian-born Abu Musab al-Zarqawi, who is allegedly linked to al-Qaida, said on Saturday they had seized three Turkish hostages and would behead them unless Turkey stopped working with U.S.-led forces in Iraq.
Turkey on Sunday rejected the demands.
"Turkey has been fighting terrorist activity for more than 20 years ... They ask many things, they demand many things. We never consider them with seriousness," Defense Minister Vecdi Gonul told reporters.
Al-Jazeera satellite channel showed footage of three men crouching before masked gunmen. It said it had received the footage and a statement from Zarqawi’s Tawhid and Jihad group, threatening to kill the Turkish captives within 72 hours.
Al Jazeera said the statement it received stated the hostages would be killed unless “Turkish forces and companies that support the occupation forces in Iraq” left by the deadline.
Sean McCormack, spokesman for the White House National Security Council, on Sunday called the threats by militants linked to suspected al-Qaida ally Abu Musab al-Zarqawi "an awful reminder of the barbaric nature of these terrorists."
"But their acts will not shake the will of free people everywhere," he said.
McCormack also said U.S. officials were in close contact with the Turkish government on the issue.
Zarqawi group claims responsibility
Zarqawi’s group beheaded a South Korean hostage earlier this week after Seoul rejected a demand to withdraw its forces from Iraq, and last month decapitated an American captive. Both killings were filmed in footage posted on Web sites used by Islamists.
Zarqawi has also claimed responsibility for a series of bloody attacks, most recently a wave of suicide bombings and armed assaults in five cities on Thursday that killed more than 100 Iraqis and three U.S. soldiers.
Speaking after a meeting with U.S. Defense Secretary Donald Rumsfeld, Gonul said up to 2,000 trucks full of medicine, food and other supplies were driving into Iraq from Turkey every day.
"These things are humanitarian. It is sad to have Turkish people (held) by some forces in Iraq. They want to help the Iraqi people," he said.
Turkey has not sent troops to join U.S.-led occupying forces in neighbouring Iraq, but many Turks work there as truck drivers and contractors for the U.S. military.
A senior U.S. defense official said the hostage issue was not discussed in the meeting with Rumsfeld, who is in Istanbul ahead of a NATO summit on Monday and Tuesday.
'A very effective terrorist'
Washington has put a $10 million bounty on Zarqawi’s head.
“He remains the number one target inside this country. He is a very effective terrorist,” Brig. Gen. Mark Kimmitt, deputy director of operations for the U.S. military in Iraq, told a news conference in Baghdad on Saturday.
U.S. forces have mounted three “precision strikes” in the rebellious Iraqi city of Fallujah over the past week aimed at destroying Zarqawi’s safehouses and killing his followers.
Kimmitt said the latest strike, on Friday, may have come close to killing the Jordanian militant. He said several cars were seen driving away from the building after it was hit.
“It’s the coalition’s assessment that it could have been Zarqawi and his key leaders,” Kimmitt said. “It may not have been. Only time will tell.”
Senior military officials said 20 to 25 militants were killed in Friday’s strike. But one Fallujah resident at the scene said no one had been killed.
“I swear to God, nobody died here except this rabbit,” said a man in an Arab robe, dangling a dead rabbit in one hand.
Iraqi guerrillas and tribal leaders in Fallujah have denied that Zarqawi is in the city. “This is a lie to excuse the strikes by occupation planes on the houses of citizens,” said a statement from the General Council of Fallujah Tribal Leaders.
Hundreds of Iraqis were killed in Fallujah in April in fierce fighting between U.S. Marines and guerrillas.
The civilian death toll caused an outcry in Iraq and a truce was agreed under which Marines pulled out of the city and handed responsibility for security to an Iraqi force. Critics say Fallujah has become a safe haven for foreign militants.