"We want to be with John again," Rose Solecki said.

"We cannot bear the shock of losing John," she said on an audiotape released by the U.N. High Commission for Refugees (UNHCR).

Solecki, head of the UNHCR in southwest Baluchistan province, was abducted on Feb. 2 by gunmen who ambushed his car and shot dead his driver in the provincial capital, Quetta.

An unheard of militant group called the Baluchistan Liberation United Front (BLUF) has claimed responsibility and threatened to kill Solecki unless the United Nations acts on its demands.

The BLUF wants the United Nations to secure the release of 141 women it says have been detained in Pakistan, provide information about more than 6,000 missing persons, and resolve the issue of Baluch independence under the Geneva Convention.

The group extended a deadline on Monday for "more days" in order to give the United Nations extra time to meet its demands.

Aside from the death threat hanging over Solecki, the United Nations fears his life could be at risk because of deteriorating health. Solecki had complained of sickness in a videotape released by his captors.

"I'm appealing to the people of Baluchistan for whatever support they can provide to secure my son safety and freedom," said his 83-year old mother.

"John has helped many people in Baluchistan and now my son needs your help," she said.

The United Nations has sought direct contact with the group holdings Solecki, without success.

Baluchistan, the largest but poorest of Pakistan's four provinces, lies on the border with Afghanistan. Separatist militants have fought a low-scale insurgency there for decades.