Taliban attacks Pakistan air force base

KAMRA, Pakistan -- Taliban fighters blasted their way Thursday into a Pakistani air force base with possible links to the country's nuclear program in a brazen assault that took two hours of fighting to put down.

The attack left a security officer and nine insurgents dead and underscored the group's continued threat despite numerous military offensives.

Hours later, Taliban gunmen in northern Pakistan forced 20 Shia Muslims off buses, lined them up and killed them, the latest in a series of sectarian attacks that the government has seemingly done little to stop.

The separate attacks emphasize two daunting challenges for Pakistan. The Taliban continue to pose a potent threat, despite numerous military offensives against their sanctuaries along the Afghan border. At the same time, sectarian violence plagues the Sunni-majority country where Shia Muslims often feel under attack.

While the Pakistani Taliban have carried out hundreds of bombings and other attacks, raids against military bases are not common. Their spokesman, Ahsanullah Ahsan, said they carried out yesterday's predawn attack as revenge for the death of Pakistani Taliban leader Baitullah Mehsud in a drone strike in 2009 and the American commando raid that killed al-Qaida chief Osama bin Laden last year.

The large Air Force Base Minhas, about 25 miles northwest of Islamabad, hosts fighter jets, including F-16s, and contains a factory that makes aircraft and other weapons systems.

The weapons development and the presence of jets that could be used to deploy nuclear bombs have raised suspicions among some experts that the base is linked to Pakistan's nuclear arsenal. No firm evidence has emerged, however. The secrecy of the nuclear program makes independent evaluation difficult. The Pakistani military denies any connection between the base and the program.

The safety of the country's nuclear weapons has been a major concern for the United States. Western experts say Pakistan has about 100 nuclear weapons and is expanding its arsenal.

"The great danger we've always feared is that if terrorism is not controlled in their country, that those nuclear weapons could fall into the wrong hands," Defense Secretary Leon Panetta told Pentagon reporters Tuesday.