(Adds details on the attack)
By Qasim Nauman
KAMRA, Pakistan Aug 16 (Reuters) - Islamist militants armed with rocket-propelled grenades and automatic weapons fought their way into one of Pakistan's largest air bases on Thursday, the air force said, in a brazen challenge to the nuclear-armed country's powerful military.
Only one aircraft was slightly damaged, an air force spokesman said, adding that the Minhas air base at Kamra, in central Punjab province, did not house nuclear weapons. "No air base is a nuclear air base in Pakistan," he said.
A gunbattle raged for hours after the attack started. Seven militants and one soldier were killed, the spokesman said.
The overnight assault challenged official assertions that military operations had severely weakened militants waging a violent campaign to topple the U.S.-backed government and impose strict Islamic rule.
Security forces opened fire on militants strapped with suicide bombing vests as they approached aircraft hangars, prompting other militants to fire rocket-propelled grenades from outside the base's walls, said the air force spokesman.
Base commander, Air Commodore Muhammad Azam, who led the operation against the attackers, was wounded, but is in stable condition, said the spokesman.
It was not immediately clear if the attack was beaten back but a Reuters reporter who reached Kamra in the morning did not hear any gunfire.
"Security personnel are now in the process of scanning the entire area to check for the presence of any other miscreant," said the spokesman.
Minhas, 75 km (45 miles) northeast of Islamabad, is adjacent to the Pakistan Aeronautical Complex, a major air force research and development centre. Pakistan manufactures JF-17 fighter planes, jointly developed with China, at the site.
Suicide bombers launched attacks near the base and the aeronautical complex in 2007 and 2009, but news reports said defences were not breached.
It was not immediately clear how the attackers managed to enter the sprawling base this time. Several squadrons of fighters and surveillance planes are believed to be housed there.
"One body of a suicide bomber strapped with explosives has been found close to the impact area," said an air force statement.
Pakistan's Taliban movement has staged a number of high-profile attacks over the past few years, including one on army headquarters in Rawalpindi in 2009.
Last year, six Taliban gunmen attacked a naval base in Pakistan's biggest city Karachi to avenge the killing of Osama bin Laden. At least 10 military personnel were killed and 20 wounded in the 16-hour assault.
Those attacks, and the latest one, are embarrassing for Pakistan's military, which has ruled the country for more than half of its 65-year history and is seen as the most efficient state institution.
The Taliban, which is close to al Qaeda, is blamed for many of the suicide bombings across Pakistan, a strategic U.S. ally.
Pakistan's military, one of the biggest in the world, has staged several offensives against Taliban strongholds in the unruly tribal areas near the border with Afghanistan.
But the operations have failed to break the back of the Taliban. Major suicide bombings have eased considerably over the past year but that could be due to a tactical shift and not pressure from the military. (Additional reporting by Jibran Ahmad in PESHAWAR; Writing by Michael Georgy; Editing by Raju Gopalakrishnan)