QUETTA, Pakistan - Kidnappers threatened on Friday to kill an American employee of the United Nations within 72 hours and issued a grainy video of the blindfolded captive saying he was "sick and in trouble."
A letter accompanying the video delivered to a Pakistani news agency said the hostage, John Solecki, would be killed unless authorities released 141 women it said were being held in Pakistan.
The video and the demands indicated that Solecki, the head of the U.N. refugee agency in Quetta, a city near the Afghan border, was alive and that his captors wanted to negotiate.
Solecki, who appeared blindfolded and with a shawl draped over his shoulders in the 20-second clip, said his message was addressed to the United Nations.
"I am not feeling well. I am sick and in trouble. Please help solve the problem soon so that I can gain my release," he said.
The kidnappers have identified themselves as the Baluchistan Liberation United Front, suggesting a link to local separatists who have waged a long insurgency against Pakistan's government rather than to the Taliban or al-Qaida, which are fighting U.S. forces in Afghanistan.
Still, the death threat heightened fears for Solecki's safety, coming just a week after Taliban militants apparently beheaded a Polish geologist abducted in another border area of Pakistan after the government failed to respond to demands for a prisoner release.
The Pole's slaying, if confirmed, would be the first killing of a Western hostage in Pakistan since American journalist Daniel Pearl was beheaded in 2002.
Gunmen seized Solecki on Feb. 2, after shooting his driver to death as they drove to work in Quetta.
Days later, the previously unknown Baluchistan Liberation United Front claimed responsibility for the kidnapping in a telephone call to the Quetta office of Online International News Network, a Pakistan-based news agency.
Online said it received an anonymous telephone call Friday telling it to collect a parcel from the post office, in which it found a memory card from a mobile phone containing the video of Solecki as well as the letter.
It supplied a copy of the video to Associated Press Television News and allowed an AP reporter to see the letter.
The letter demanded the release of 141 women from Pakistani custody and said the group would issue another list of hundreds of alleged male prisoners. "We will issue this list very soon. If our demands are not met, we will murder John Solecki," it said.
The commander of a government paramilitary unit in Quetta dismissed the claim of female prisoners as fiction.
"Who are these 141 women? Who knows who they are? This is just attention-seeking. This is just terrorism," Maj. Gen. Salim Nawaz told the Aaj television network.
Nawaz said that "powers who want to destabilize Pakistan" were manipulating ethnic Baluch separatist groups - language usually used by Pakistani officials to mean archrival India.
Maki Shinohara, a spokeswoman for the United Nations, said it had not been able to establish contact with the kidnappers. She said officials were scrambling to work out how to respond to the threat and the demands.
At United Nations headquarters in New York, U.N. associate spokesman Farhan Haq said the world body was studying the video to determine what to do next.
"We have seen the video and based on what we can see, it appears to be the person in the picture is John Solecki," Haq said. "Our team in Islamabad continues to examine the information. We have nothing further to add at this time beyond reiterating our appeal that John be released."
U.S. Embassy officials could not be reached late Friday for comment.
A string of attacks on foreigners near Pakistan's border with Afghanistan in recent months have highlighted authorities' crumbling control in the face of an intensifying Islamic insurgency.
Afghanistan's ambassador-designate, an Iranian diplomat and a Chinese telecoms engineer have been seized in or near the main northwestern city of Peshawar and are still missing. Gunmen killed an American aid worker in Peshawar in November.
While Quetta has been relatively calm, Afghan officials have repeatedly described it as a hub for Taliban leaders orchestrating the insurgency across the border. Pakistan's denies that.