PESHAWAR, Pakistan (AFP) - Militants holding two Chinese engineers in a rugged tribal area near the Afghan border have threatened to kill them unless Pakistan releases Al-Qaeda detainees, a security official said.
"There is only one demand. They have asked for the release of all arrested foreign militants," the intelligence official, based in the northwest city of Peshawar, told AFP on condition of anonymity.
"They have given the government one day to consider their demand, otherwise they said they will kill the hostages."
The four captors -- three foreign militants and a local tribesman -- issued the demands on Saturday, the official said.
The engineers were kidnapped Saturday morning as they travelled to the Gomalzam dam project in South Waziristan, the remotest and most dangerous of Pakistan's northwest tribal districts. The dam lies around 75 kilometers (46 miles) from the mountainous Afghan frontier.
Police identified the Chinese as Wang Teng and Wang Ende.
China's embassy in Islamabad was unaware of the threat and demand. It had been told the engineers were safe and in the custody of a local tribe.
"According to our information at this moment our two Chinese engineers are still safe but they have yet to be released," said spokesman Zhang Yiming.
"We are informed that the Chinese engineers and the kidnappers are separately under the custody of local tribal elders, and that they are safe this moment."
North West Frontier provincial home secretary Abdul Karim Qasuria said they were being held near the dam in an area called Jandola. The local Mahsud tribe and religious leaders were negotiating with the captors, he said.
"They are hopeful of ending the crisis peacefully," Qasuria said.
Aurdin Khan, one of the negotiators, told AFP that a tribal leader called Abdullah Mahsud has announced that his men carried out the kidnapping.
He quoted Mahsud, who has been fighting security forces, as saying his men "took the action because of repeated bombings and shelling by Pakistani forces in the area".
Mahsud was quoted as saying that "the step has been taken reluctantly because China is not only a good friend of Pakistan but the people of both countries also respect each other".
Mahsud, speaking to the negotiators at an undisclosed location, was quoted as saying that security forces surrounding the area should allow his men to bring the Chinese to him so a release can be negotiated.
He said the captives would be safe in his custody but any rescue attempt would endanger their lives.
Hundreds of Al-Qaeda militants have taken refuge and set up training camps in South Waziristan, and have been battling thousands of Pakistani army troops trying to flush them out.
Clashes between security forces and militants linked to Al-Qaeda broke out near Jandola in recent days.
Pakistan has captured around 600 Al-Qaeda suspects in the past three years but handed the majority over to United States custody.