Afghanistan-based Taliban leader Maulvi Fazlullah, a leading figure in the insurgency, has vowed to return to Pakistan to wage war as the country came under renewed American pressure to tackle militancy.
"We sacrificed our lives, left our homes and villages for the sake of Sharia (Islamic Law) and will do whatever we can to get Sharia implemented in the Malakand region and rest of Pakistan," Sirajuddin Ahmad, a close adviser, told Reuters, describing Fazlullah's position.
He was answering written questions submitted by Reuters.
The Taliban threat was issued as U.S. Secretary of State Hillary Clinton and top U.S. military and intelligence leaders delivered a tough warning to Pakistan to crack down hard on militant groups, an issue heavily straining ties between the uneasy allies.
Fazlullah was the Pakistani Taliban leader in Swat Valley, about 100 miles (160 km) northwest of Islamabad, before a 2009 army offensive forced him to flee.
Also known as FM Mullah for his fiery radio broadcasts, he regrouped in Afghanistan and established strongholds, and poses a threat to Pakistan once again, said army spokesman Major-General Athar Abbas.
The Pakistani Taliban, which is separate from but aligned to the Afghan Taliban fighting foreign forces in Afghanistan, has declared war on the Pakistani state for providing support to the U.S.-led war on militants in the region.
Pakistan recently complained that Afghan and U.S.-led forces had failed to hunt down Fazlullah who was responsible for a spate of cross-border raids.
On the other hand, Afghanistan and the United States have accused elements in the Pakistan government of supporting members of the Afghan Taliban.
The attacks in which militants loyal to Fazlullah took part killed about 100 members of Pakistan's security forces, angering the army which faces threats from multiple militant groups.
Fazlullah, a leading figure in the Pakistani Taliban insurgency, is based in Kunar and Nuristan provinces in Afghanistan, said Abbas.
Other leaders of the Pakistani Taliban, an umbrella of about 12 groups, and the government have suggested they are open to peace talks to end a conflict that has killed thousands of people.
But Fazlullah seemed sceptical about the government's intentions.
"Pakistani rulers always approach us through some people whenever their relations with the United States become unfriendly and make appeals to us to help them in restoration of peace in the country," said his adviser.
"But they forget their promises and become more harsh and cruel when their relations are restored with the United States. We know these tricks of the Pakistani rulers and do not trust in their promises."