Watch beheading (here)
The Islamist militants said on Saturday they had executed the Polish engineer, Piotr Stanczak, who they kidnapped in September, because the government had refused to free 60 captured militants before Friday's deadline.
A tape was delivered to the office of a Reuters reporter in the northwestern town of Dera Ismail Khan showing two masked men cutting off Stanczak's head.
Before he was killed, Stanczak was seen on the tape appealing to the Polish government not to send troops to Afghanistan.
He also urged Poland to severe ties with Pakistan, which he said had made no effort to secure his release, said a Reuters reporter who saw the tape.
Assaults 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 government forces are battling the Taliban and al Qaeda.
A Taliban spokesman, identified only as Mohammed, said earlier the militants would only give up Stanczak's body if the government freed captured militants and stopped attacking them.
"We will not hand over the dead body if the government does not accept our demands," the Taliban spokesman said by telephone.
"Our demands are the same: the release of our 60 men and an end to military operations."
Polish Prime Minister Donald Tusk on Saturday said his government had received unofficial confirmation the 42-year-old hostage was dead.
Stanczak was kidnapped on Sept. 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 abducting him.
An American heading the United Nations High Commissioner for Refugees (UNHCR) office in southwestern province of Baluchistan, was taken 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.
A militants on the tape released on Sunday said other foreign hostages including the Chinese engineer would also be killed if the government did not meet Taliban demands.