A suicide attack on an Air Force bus killed eight people on Thursday as security forces said they wiped out up to 70 militants in northwest Pakistan, fuelling talk President Pervez Musharraf would invoke emergency powers to put off elections.Nuclear-armed Pakistan is going through a period of intense uncertainty in the run up to a vote due in January that is supposed to transform the country into a civilian-led democracy.“With reference to extremists and terrorists, it’s a bad situation,” said Javed Iqbal Cheema, head of the Interior Ministry’s Crisis Management Cell.“It’s a very serious threat to Pakistan’s internal security.”The Supreme Court added to tensions on Thursday by dragging out hearings on whether US ally General Musharraf was eligible to have stood for re-election while still army chief in a vote in parliament that he won easily early last month.The Karachi stock exchange’s benchmark index dropped nearly three percent on Thursday, compounding declines earlier this week as investors turned tail in a market that is still 38 percent up since the start of the year.Before the market opened, a suicide bomber rammed a bus and killed eight personnel on their way to an air base in Sargodha in the central province of Punjab.Police said they had found the head of the bomber, and circled blood stains on the road with white chalk, while the handlebars of a motorbike used by the attacker lay on the tarmac.Separately, troops killed up to 70 militants as fighting flared in Swat valley in North West Frontier Province, where more than 180 people have died since last week as the military battles a pro-Taliban movement seeking toimpose strict Islamic law.The latest violence coincided with a visit by Admiral William Fallon, commander of US Central Command, for talks with the Pakistani military leadership.Nearly 800 people have been killed in militant-linked violence and there have been more than 22 suicide attacks in the four months since Pakistani commandos stormed the Red Mosque in the capital, Islamabad, to crush a Taliban-style movement.Al-Qaeda leaders Osama bin Laden and Ayman al-Zawahri, in audio and video tapes released in September, exhorted followers to wage war on Musharraf and Pakistan’s security forces.“The last battle between Islam and the infidels is on. On the one side is Sheikh Osama, may Allah keep him safe,” Maulvi Faqir Mohammad, one of the most wanted militants in Pakistan told approving ranks of fighters in Bajaur tribal region, near Swat.“We assure him and Mullah Omar, and mujahideen all over the world that we stand solidly behind you.”Yet investors have been more worried about the Supreme Court destabilizing Musharraf, who came to power in a coup eight years ago, than the burgeoning militant threat.The court said it will adjourn after Friday’s session until November 12 — just three days before Musharraf’s present term expires, with parliament also coming to the end of its term.