Pakistani troops gather next to a burnt plane inside the naval aviation base following an attack by militants in Karachi, Pakistan, Monday, May 23, 2011. – Photo by AP

KARACHI: The bullet-proof vehicles pressed into service to evacuate foreigners from the Pakistan Navy’s Mehran base immediately after Sunday night’s armed assault were attacked by the raiders who appeared to be aware of the emergency evacuation plan, security sources told Dawn on Tuesday.

It was because of the bullet-proof vehicles that the foreigners — six Americans and 11 Chinese — were safely evacuated, said the sources. They added that the vehicles had been hit by bullets, but were not damaged.

The sources also said that American contractors were working on a project to upgrade P-3C Orion aircraft.

It was not before dawn that security forces launched a final assault on the raiders and eliminated them.

Until sunrise, a portion of the base was in control of the assailants, the sources said.

Ten security personnel were killed and 15 others injured in the 16-hour operation launched to regain control of the base.

Two attackers were hunted down in bushes as they apparently made a run or attempted to hide, the sources said.

Two others blew themselves up when security personnel surrounded a building they were in, the sources said, adding that the structure was damaged in the blasts.

The officer-in-charge had earlier tried to negotiate with them, demanding that they lay down their weapons. But their reply was: “We know what you are going to do with us once we surrender.” Subsequently, they blew themselves up, the sources said.

The officer who attempted to negotiate with the attackers said that the two spoke Urdu clearly and from their accent they appeared to be locals.

As explained by Interior Minister Rehman Malik, the raiders took advantage of a blind spot that was not covered by security cameras at the rear boundary wall of the base along a storm-water drain.

They entered the base by cutting the barbed wire and using a ladder to scale the wall.

It was during a search after the operation that security personnel found the cutter and the ladder at the place.

The militants covered an approximate distance of one and a half kilometres from the wall up to the hangar where two P-3C Orion aircraft were parked and attacked the planes with rocket-propelled grenades.

They then moved on and occupied two nearby buildings where they took positions. The militants also took control of “Tower No.8”. After taking up the positions, they kept firing at the security personnel who tried to move towards them or the aircraft.

Perhaps the first casualties were of the naval firemen who were rushing towards the blazing aircraft to douse the fire.

Inside sources said there was so much confusion that security personnel kept trying to use the same road leading to the hangars ahead of which the raiders had taken positions, instead of using an alternative road running along the rear wall that also led to the place.

It was for this reason that most casualties among security personnel took place in one particular area of the base, the sources said.