Pro-Taliban militants in Pakistan warned on Saturday they would behead some 30 tribal elders if they continued "spying" for US forces in neighbouring Afghanistan, officials said.
"This is the last warning. They must stop spying for the Americans or we will behead them," read a letter distributed in the border town of Angoor Ada in the semi-autonomous tribal region of South Waziristan, an official said.
"We have done it the past and we can do it in the future also," said the letter, which listed the names of several tribes, according to the official.
Several tribesmen have been shot dead or beheaded this year for allegedly spying for US-led forces in Afghanistan or supporting Pakistan's campaign against al Qaeda and other militants in the area.
The warning comes some two weeks after militants shot dead a tribesman in Angoor Ada after accusing him of spying for US troops. South Waziristan had been quiet after a major offensive there in early 2004, - with the violence moving to North Waziristan - but earlier this month five Pakistani soldiers were wounded there when militants threw a bomb into a house.
Key US ally Pakistan has deployed some 80,000 troops to hunt down Taliban and al Qaeda fighters who are believed to have sneaked into the tribal terrain after the fall of the Taliban regime in Afghanistan in late 2001.