Islamabad - Pakistani government on Saturday dismissed the demands of the captors of a United Nation's official as unrealistic but expressed willingness to negotiate with them.

A separatist group in Pakistan's south-western Balochistan province set a 72-hours deadline on Friday to kill John Solecki, the local head of the United Nations High Commissioner for Refugees, if 141 women held in the torture cells of country's intelligence agencies were not freed.

The Baloch Liberation United Front (BLUF), a secular and nationalist guerrilla organization seeking independence from Pakistan, also demanded the release of 6,000 more political prisoners.

"These are unrealistic demands," said Pakistan's top security official Rehman Malik. "We categorically deny that we have any ladies in our custody."

Malik asked the families of any women believed to be in the custody of law enforcers to come forward and contact the authorities so that their release could be ensured.

He also denied that there were any male political prisoners in Balochistan province.

"Whoever has done this (abducted Solecki) wants to defame the country," Malik told reporters in Balochistan's capital Quetta, where Solecki was snatched on January 2 after unknown gunmen shot dead his driver.

Solecki appeared blindfolded in a video released by BLUF late Friday. "My message to the United Nations. I am not feeling well. I am sick. I am in trouble. Please help to resolve the problem soon, so I can gain my release," he appealed.

A UN spokeswoman said Saturday that Secretary General Ban Ki-Moon has lodged an appeal with the Pakistani government to take all steps possible to ensure Solecki's release. In his plea, Ban noted that Solecki's work is beneficial to large parts of Balochistan's population.

Hundreds of people have died in nationalist insurgency in Balochistan since 2005 when rebels resorted to an armed campaign for greater share of the province's oil and gas wealth.

A BLUF spokesman asked Ban on February 7 to take notice of enslavement of Balochistan politically, culturally and socially by Pakistan, as the group claimed responsibility of UN officials' kidnapping.

Malik said the authorities had some clues about Solecki's captors and hoped that the UN official would seen be recovered safely. He declined to give any further details. (dpa)