KABUL, Afghanistan - A militant group claiming responsibility for kidnapping three foreign U.N. workers said Saturday that it will execute them unless Britain withdraws its troops from Afghanistan and two other governments stop supporting U.S. policy here.

A spokesman for Jaish-al Muslimeen, a splinter group of the Taliban, told The Associated Press it had made a video of the three hostages - but provided no evidence that it was holding the trio.

Unidentified armed men kidnapped Filipino diplomat Angelito Nayan, Kosovan Shqipe Habibi and Annetta Flanigan from Northern Ireland in downtown Kabul on Thursday. All were helping organize Afghanistan's election.

"If these countries don't agree to our demands, we will do the same thing as the mujahedeen are doing in Iraq," Ishaq Manzoor, a purported spokesman for Jaish-al Muslimeen, or Army of Muslims, said by satellite telephone.

Manzoor, who said he was speaking from near the Afghan-Pakistan border, close to the eastern Afghan city of Jalalabad, also demanded the release of all Afghan detainees from the U.S. prison in Guantanamo Bay, Cuba, and that the search for the abductees be called off.

"We may kill them if we could not get a positive response," he said.

He said the video would be released "in two or three days" to an Arab television channel.

He also provided what he said were the numbers from identity cards found on two of the hostages. He was unable to say what kind of cards they were taken from.

Afghan and U.N. officials had no immediate comment on the validity of the ID card numbers.

Naveed Moez, an Afghan Foreign Ministry spokesman, said the government had received no specific demands from the kidnappers, but added that "government sources have confirmed" media reports of Jaish-al Muslimeen's claim of responsibility.

Moez said the 18,000-strong U.S.-led force in Afghanistan and the Ministry of Interior were trying to hunt down the kidnappers. "I don't think there's any sort of negotiations going on."

Police on Friday detained seven suspects for questioning over the kidnappings, but had not established any link to the abductions, Interior Minister spokesman Latfullah Mashal said.

Three of the suspects picked up in the Kabul area were carrying arms and wearing military uniforms - fitting descriptions from witnesses.

Mashal said the vehicle used by the kidnappers was seen heading toward Paghman, a district west of Kabul with a reputation for banditry, and authorities had obtained the license number but had yet to trace its owner.

Security was also tightened in the capital, where police accidentally shot a United Nations driver Saturday morning.

U.N. spokesman Manoel de Almeida e Silva said guards opened fire after another vehicle failed to stop at a checkpoint, and hit a driver of a car from the U.N.'s in-house airline.