(Recasts with six killed, adds details, quotes and background throughout)
By Gul Yousufzai
QUETTA, Pakistan, Aug 14 (Reuters) - Six militants were killed and 13 members of the Pakistani security forces were wounded in attacks on two air force bases in the strategic west Pakistan city of Quetta on Thursday, officials said.
While the attackers did not get inside either facility, the raids marked the third time since June Pakistani airports had been targeted and will raise more questions about how secure such facilities are.
There was no immediate claim of responsibility for Thursday night's attacks but the Pakistani Taliban said they had carried out the two previous raids. Pakistan's military is fighting an offensive against the Taliban insurgency in the remote, largely lawless region of North Waziristan on the Afghanistan border.
Police said three attackers were killed at the Samungi air force base, which shares a runway with the civilian airport in Quetta, a strategic city that has long been used by both the Afghan and Pakistani Taliban.
Another three were killed at Khalid air force base, said provincial Inspector General, Muhammad Amlish.
Residents near Samungli air force base heard at least eight blasts and gunfire that continued for around half an hour. Helicopters also buzzed overhead, they said.
Amlish said two suicide bombers blew themselves up at Samungli in an effort to get inside. He said residents had alerted police to a suspect vehicle near the Khalid air base.
Four bombs were defused there, said Sarfraz Bugti, home minister in the provincial government of Baluchistan.
"The situation is under control. No terrorists succeeded in entering the air base or Quetta airport," said Amlish.
In June, a Taliban attack killed 30 people at the airport in Karachi, the southern city that is home to 18 million people.
That attack followed months of faltering peace talks between the government and the Taliban. The Taliban had refused to renounce violence while the talks were underway.
Days after the Karachi airport attack, the military launched its long-awaited offensive in North Waziristan, a region considered the Taliban's major stronghold. Pakistan's allies, including the United States, had long urged the military to move against Taliban havens there.
The same month, militants fired on a plane landing in Peshawar, a provincial capital in the northwest, killing one woman passenger and narrowly missing the pilot. Peshawar airport was also attacked in 2012, when nine people were killed.
In 2012, nine people were killed in an attack on an air force base in the northern city of Kamra.
Pakistan's government and military are fighting a home-grown insurgency but Quetta has also long been a stronghold for the Afghan Taliban. The leadership of the Afghan Taliban fled to the city after their government was toppled by U.S.-backed Afghan forces in late 2001.
More recently, the attention of Pakistani security agencies has been focused on two large anti-government protests that are due to reach the capital on Friday.
Opposition politician Imran Khan and cleric Tahir ul-Qadri have said they want to force the government to step down and will camp out in the streets of the capital until it does so. (Writing by Katharine Houreld; Editing by Paul Tait)