A suicide bomb attack on a Pakistani Air Force bus has killed at least eight people and wounded several more. The attack comes as officials reported some 70 more militants have been killed in the latest fighting in northwest Pakistan's Swat valley. VOA's Barry Newhouse reports from Islamabad.

Government officials in Pakistan's Northwest Frontier Province said security forces and pro-Taliban militants continued heavy fighting Thursday for control of Swat valley.

Provincial Home Secretary Badshah Gul Wazir said the latest fighting started when militants attacked a post of security forces.

He said government forces and militants fought using heavy weapons and 70 militants died in the battle. He denied reports that dozens of security forces have been surrounded in one region and were preparing to surrender. He said militants have been using hit-and-run attacks and not fighting pitched battles.

Residents reported artillery fire and helicopter air strikes in the valley Thursday. Thousands of people have fled the region, and the government has set up temporary camps for some of the displaced.

Far southeast of Swat, in Punjab province, a suicide bomber rammed a bus carrying Air Force personnel, killing eight people. The attack was the latest in a series of suicide bombings against military and political targets in Pakistan.

The violence comes as Pakistan's high court considers several politically charged cases that could dramatically alter upcoming national elections. On Thursday, justices heard arguments in a case challenging President Pervez Musharraf's unofficial reelection as president.

A judge dismissed speculation that the court would be swayed by rumors that General Musharraf would declare martial law, if the court rules against him. The judge insisted the legality of his re-election would be decided under Pakistan's constitution.

Mr. Musharraf's political rival, former Prime Minister Benazir Bhutto, flew to Dubai on Thursday to visit her family. She arrived in Pakistan last month after an eight-year absence, but the homecoming was marred by a suicide attack that killed more than 140 people.