KARACHI, Pakistan (AP) -- Pakistani commandos cornered a team of Taliban militants in a naval base Monday after the insurgents raided the complex the night before, destroying two U.S.-supplied surveillance aircraft and killing at least 12 security officers, the navy said.
The Pakistani Taliban claimed responsibility for the assault in the city of Karachi, saying it was part of their revenge for the May 2 American raid that killed al-Qaida chief Osama bin Laden and that their men were under orders to fight until the death.
"They do not want to come out alive, they have gone there to embrace martyrdom," said spokesman Ahsanullah Ahsan.
Between 10 and 15 insurgents armed with grenades, rockets and automatic weapons stormed Naval Station Mehran late Sunday before splitting into smaller groups, setting off explosions and hiding in the sprawling facility. Some or all of them were still holding out 12 hours later, navy spokesman Irfan ul Haq said.
The raid was one of the most audacious in years of militant violence in Pakistan. The insurgent's ability to penetrate the high-security facility rattled a military establishment already humiliated by the unilateral American raid on Bin Laden, and raised the possibility they had inside help.
At least 11 navy personnel and one paramilitary ranger were killed, while 14 security forces were wounded, Haq said, adding it was unclear how many militant casualties there were.
The attack resembled the 2008 siege of Mumbai, India, and a number of other similar raids in Pakistan in which heavily armed squads of insurgents go out in teams, occupy a property and fight to the death. It was one of the first such strike in Karachi, the country's largest city and economic hub.
When asked about reports of hostages, Haq said the militants were "not in possession of anything." By Monday morning, the militants were confined to an office building, trading fire with commandos, he said. Navy helicopters were flying over the base.
"Because of the presence of several assets on the base, the operation is being carried out in a cautious, smart way," Haq said, referring to military aircraft. "That's why it's taking so long."
The unilateral U.S. raid on bin Laden's compound in the northwest Pakistani garrison city of Abbottabad has triggered a strong backlash here against Washington as well as rare domestic criticism of the armed forces for failing to detect or prevent the American operation. Pakistani leaders insist they had no idea the al-Qaida boss had been hiding in Abbottabad.
In claiming responsibility, Pakistani Taliban spokesman Ahsanullah Ahsan said the attack was part of their planned response to the death of the al-Qaida chief, and that Pakistan is the top target. The Pakistani Taliban hate the government in Islamabad because of its alliance with the U.S. and because, under American prodding, the Pakistani army has staged offensives aimed at its insurgents.
This is the third major attack the group has claimed since the bin Laden killing, including a car bombing that slightly injured American consulate workers in the northwest city of Peshawar and a twin-suicide attack that killed around 90 Pakistani paramilitary police recruits.
Sunday's raid appeared to be the most serious against the military since October 2009, when militants attacked the army headquarters close to the capital, Islamabad. They held dozens hostage in a 22-hour standoff that left 23 people dead, including nine militants.
The fact that militants were able to enter the naval base late Sunday is another embarrassing blow to the Pakistani military. Just as the October 2009 attack on the army headquarters did, it raises speculation over whether anyone in the military ranks aided the insurgents. Many in Pakistan's military establishment are believed to have sympathy for Islamist causes.
That the militants this time targeted U.S.-supplied aircraft draws attention to American aid to the military, something generals here do not talk about, fearing criticism from the county's fiercely anti-American population.
Pakistani Prime Minister Yousuf Raza Gilani condemned the attack, saying such a "cowardly act of terror could not deter the commitment of the government and people of Pakistan to fight terrorism."
The raid began with at least three loud explosions, which were heard by people who live around the naval air station. It was unclear what caused the explosions, but they set off raging fires that could be seen from far in the distance. An Associated Press reporting team outside the base heard at least six other explosions and sporadic gunfire.
Authorities sent in several dozen navy and police commandos to battle the attackers, who responded with gunfire and grenades, said Salman Ali, another navy spokesman. At least two P-3C Orions, maritime surveillance aircraft given to Pakistan by the U.S., were destroyed, he said.
The United States handed over two Orions to the Pakistani navy at a ceremony at the base in June 2010 attended by 250 Pakistani and American officials, according to the website of the U.S. Central Command. It said by late 2012, Pakistan would have eight of the planes.
At least one media report said a team of American technicians were working on the aircraft at the time of the strike, but U.S. Embassy spokesman Alberto Rodriguez said no Americans were on the base. Ali also stated there was no foreigners inside the base.
Karachi, a city of around 18 million people, has not been spared the violence sweeping the country, despite being in the south far from the northwest where militancy is at its strongest. In April, militants bombed three buses taking navy employees to work, killing at least nine people.
The Pakistani Taliban and other militant groups have little direct public support, but the army and the government have struggled to convince the people of the need for armed operations against them. The militants' identification with Islam, strong anti-American rhetoric and support for insurgents in Afghanistan resonates with some in the country.
Associated Press writers Ishtiaq Mahsud in Dera Ismail Khan and Rasool Dawar in Peshawar contributed to this report.
(Copyright 2011 by The Associated Press. All Rights Reserved.)