LAHORE: Pakistani security officials have detained a former navy commando and his brother in connection with last week's militant attack on a naval air base, intelligence officials and relatives said on Monday.

The brazen assault on the PNS Mehran base in Karachi, the headquarters of Pakistan's naval air wing, embarrassed the military and raised doubts about its ability to protect its bases after a similar raid on the army headquarters in the city of Rawalpindi in 2009.

Kamran Ahmed, who was sacked from the navy about 10 years ago, and his younger brother, Zaman, were picked up from the eastern city of Lahore on Friday, five days after the attack that killed at least 10 military personnel.

“They have been detained in connection with the naval base attack and are under interrogation,” one intelligence official said, without giving details.

Imran Ahmed, another brother who was not arrested, told Reuters the two were taken away by intelligence officials on Friday. He gave no details.

An earlier arrest of a suspect in the Mehran base attack led to the arrest of the Ahmed brothers.

A second intelligence official said Kamran Ahmed served at Mehran and was court-martialed for assaulting a senior officer.

The military court declared him mentally unfit for the job.

He was also under suspicion after a suicide attack on the naval war college in Lahore in 2008 but was not detained, the official said.

“The suspect arrested earlier said Ahmed provided information about the base to a militant network, which carried out the attack.”

The Pakistani Taliban, which is allied to al Qaeda, claimed responsibility for the attack on the Mehran base, but many analysts believe they had inside help.

A group of between four and six militants besieged the base for 16 hours and destroyed two P-3C Orion aircraft from the Unites States, crucial for Pakistan's maritime surveillance capabilities.