KOHAT, Pakistan (Reuters) - Taliban fighters beheaded a Polish hostage in Pakistan Saturday, according to a spokesman for the militants who said the body wouldn’t be handed over until some captured Taliban were released.

Speaking in Germany, Polish Prime Minister Donald Tusk said his government had received “unofficial confirmation” Piotr Stancza, an engineer and a father of one, had been killed.

“We do not have a solid proof but we have received unofficial confirmation that this tragedy indeed took place,” Tusk told reporters in Munich in comments broadcast live on Polish TV.

The Taliban spokesman, identified only as Mohammed, told Reuters Stancza, 42, was killed because Pakistani authorities failed to free the militants before a deadline expired at midnight Friday.

“We have killed the man after authorities refused to release our colleagues,” the Taliban spokesman told Reuters. “We will now only hand over his body after our demands are met.”

He said Stanza was executed in the south Waziristan tribal region, a known haven for Taliban and Al Qaeda fighters.

An intelligence official in the region, who requested anonymity, said the Taliban had demanded 200,000 rupees ($2,540) in exchange for the body.

Officials were unable to verify the Taliban claim, and the two principal hostage negotiators handling Stancza’s case could not be reached for comment.

Speaking on the sidelines of a security conference in Munich, Prime Minister Donald Tusk told reporters:

“We have used every opportunity to avert this.”

Stancza was kidnapped on September 28 while visiting one of his company’s sites near Attock city, about 65 km (40 miles) west of the capital, Islamabad.

Gunmen shot dead his Pakistani driver, bodyguard and translator before taking him hostage.

Militants had demanded 60 of their comrades should be freed, but later cut their demand to four of their top men and negotiations have intensified over the past 10 days.

Attacks on foreign aid workers, company employees and diplomats have increased in Pakistan over the past year, especially in areas near the border with Afghanistan, where Taliban and al Qaeda militants are battling government forces.

An American heading the United Nations High Commission for Refugees (UNHCR) office in southwestern province of Baluchistan, was abducted last week and his driver was shot dead.

Two Chinese telecommunication engineers, two Afghan diplomats and an Iranian diplomat were kidnapped in northwest Pakistan, though one of the Chinese later escaped.