Heavily armed suspected Islamist militants Thursday attacked one of Pakistan's largest air bases, resulting in an intense firefight for several hours that left seven gunmen and two security personnel dead.

The gunmen, some of them reportedly wearing military uniforms, attacked the Minhas air base at Kamra, in central Punjab province at about 2 am in a brazen challenge to the nuclear-equipped nation's powerful military, agencies reported.

All Pakistani airbases are under high alert following the attack.

About 10 attackers breached at least three barriers and tried to target Saab-2000 surveillance aircraft, Press Trust of India reported citing TV reports. However, the number of gunmen has not yet been officially confirmed.

Dismissing early rumors that Minhas airbase housed nuclear weapons, an air force spokesperson said, "No airbase is a nuclear base in Pakistan," Reuters reported.

Minhas is one of Pakistan's biggest air bases with about 30 fighter jets, including new JF-17 planes that are being assembled there, the BBC reported. It is about 60-km (35 miles) north-west of Islamabad.

The security troops opened fire on militants strapped with explosive vests as they approached aircraft hangars while other militants fired rocket-propelled grenades from outside the base's walls, the air force spokesman was quoted as saying.

Base commander, Air Commodore Muhammad Azam, who headed the operation against the gunmen, was wounded, but was in stable condition while one aircraft was slightly damaged, said the spokesman.

Security personnel were still scanning the premises for any other gunmen unaccounted for when this report was filed.

It remains unclear how the attackers entered the base under high surveillance.

No militant group has claimed responsibility for the attack.

Citing intelligence reports, Pakistani media reported August 10 that the Tehrik-e-Taliban could target the air forces facilities in Punjab before Eid-ul-Fitr on 27th or 28th of the Islamic holy month of Ramadan (Aug. 16 and 17).

Pakistan's Taliban has carried out similar attacks in the past, including one on the army headquarters in Rawalpindi in 2009.

The Taliban, who have ties with al-Qaeda, attacked a naval base in Karachi in May last year in response to the killing of Osama bin Laden. Ten security personnel were killed and 20 others injured in the attack.