ISLAMABAD, Pakistan - Despite the growing threat from Islamic extremists, President Pervez Musharraf said U.S. troops are not welcome to join the fight against al-Qaida on Pakistani soil.
Musharraf warned in an interview published Friday that Pakistan would resist any unilateral military action by the United States against militants sheltering in its lawless, tribal regions close to the Afghan border.
"I challenge anybody coming into our mountains," he told Singapore's The Straits Times in the interview notable for its unusually strident language. "They would regret that day."
The Pakistan-Afghan border has long been considered a likely hiding place for al-Qaida leader Osama bin Laden and his top deputy Ayman al-Zawahri, as well as a staging ground for Taliban militants planning attacks on coalition forces in Afghanistan.
The New York Times reported last week that Washington was considering expanding the authority of the CIA and the U.S. military to launch aggressive covert operations within the tribal regions. Several U.S. presidential candidates have also hinted they would support unilateral action in the area.
On Friday, State Department spokesman Tom Casey said that anything the U.S. has done, and anything it will do, has been "in full cooperation" with Pakistan's government.
Musharraf said U.S. troops would "certainly" be considered invaders if they set foot in the tribal regions without his permission. A full transcript of the interview was published on the paper's Web site.
Musharraf also said in the interview that he would resign if opposition parties tried to impeach him after parliamentary elections set for Feb. 18.
Pakistan's opposition is expected to make gains in the elections amid widespread sympathy for opposition leader Benazir Bhutto, who was assassinated Dec. 27. Opposition groups say they would try and oust the president, although it is still doubtful they could muster the two-thirds parliamentary majority required.
Musharraf -- who seized power in a military coup eight years ago -- is seen as vulnerable to impeachment over his decision to fire Supreme Court judges and suspend the constitution last year.
"If that (impeachment) happens, let me assure that I'd be leaving office before they would do anything. If they won with this kind of majority and they formed a government that had the intention of doing this, I wouldn't like to stick around," he said. "I would like to quit the scene."
On Thursday, a suicide bombing by a suspected Islamic extremist in the eastern city of Lahore killed 24 people in the first major attack since Bhutto's assassination. All but three of the dead in the bombing outside the High Court were police officers.
Investigators reconstructed the face of the suicide bomber and took prints off his severed fingers on Friday as they probed the attack, which exposed Pakistan's growing vulnerability to Islamic extremists ahead of the elections.
The bombing was the latest in a series of at least 20 suicide attacks in the country over the past three months that have killed around 400 people, many of them security officers.
Lahore police released a photo of the bomber -- who appears to be around 30 years old with medium-length black hair and a thin mustache and beard -- after reconstructing his mutilated face. Investigators also recovered prints from two of his fingers and were trying to match them with those in a national database, said Lahore anti-terrorism police officer Masood Aziz.