At least 4 people were killed in an attack that took place in Karachi around 10:30 p.m. at one of Pakistan's naval aviation base on Sunday, reported Reuters.

The attack, which was carried out by more than a dozen gunmen, blew up an aircraft and the gunmen kept fighting inside one of the country's most heavily guarded installations.

Commander Salman Ali, a Navy spokesman said, They were carrying guns, rocket propelled grenades (LPG) and hand grenades. They hit the aircraft with an RPG. The attackers are numbered up to 15.They are still inside the base, he added, the report said.

Officials said that 3 hangars housing aircrafts had been targeted in the attack on PNS Mehran in the southern city of Karachi. Jet fuel tanks possibly caught fire in the 9 explosions reported from the base.

It could not be established immediately as to who is behind this attack. Taliban's involvement with the blast cannot be ruled out since the Taliban militant's have carried out several attacks in the country after the killing of Al Qaeda leader Osama bin laden on May 2nd.

 We have been able to confine them to one building and an operation is underway either to kill or capture them, said interior Minister Rehman Malik. He also said that the militants had attacked from the rear of the base.

As soon as the attacks began, Pakistani military and paramilitary reinforcements rushed with 4 vehicles carrying about 10 troops each moving into the base, the report said.

Media reported that the militants made their way to the base through a sewer line, but the reports have not been confirmed. The military is aiming to capture as many gunmen alive as possible, reported a Pakistan television channel.

No foreign nationals have been reported to be on the base during the attack.

According to an official, two people, 1 naval officer and 1 firefighter were killed and 2 others injured. He said at least 4 people were killed.

Prime Minister Yusuf Raza Gilani, on this attack said in a statement, Such a cowardly act of terror could not deter the commitment of the government and people of Pakistan to fight terrorism.