Pakistan navy has declared that the operation involving an attack by armed men on a military base in the Pakistani city of Karachi has come to an end, according to Al Jazeera's sources.
According to a navy spokesman, 11 navy officers and two paramilitary ranger have been killed and 14 others injured in the attack that lasted for hours before ending past midday on Monday.
At least a dozen men attacked the Mehran base, a key naval aviation facility, late on Sunday. Two maritime patrol aircraft were destroyed and at least nine people were also wounded in the assault.
"The navy was in a high state of alert," Al Jazeera's Kamal Hyder said, adding that "the attack raises a lot of questions as to how such a large number of people, so well armed, could have actually gotten into the base".
Rehman Malik, Pakistan's interior minister, said the "terrorists" sneaked into the base from three points adjacent to residential areas in the city of 16 million people, whose port is a vital hub for NATO supplies bound for Afghanistan.
"A building in the premises is still under their occupation from where they are exchanging fire with our soldiers," Malik said on Monday.
"It is not just an attack on navy establishment, it is an attack on Pakistan," Malik added, warning that those who sympathise with the Taliban and al-Qaeda should instead "join hands with us to save our country".
Talat Hussain, a senior Pakistani journalist, told Pakistan's Dawn News that "We need to realise that this is not just an incident. The reality is that Pakistan is under attack, it is not just a security breach."
Earlier a spokesman for the Pakistani Taliban said that the team of militants they sent into Karachi's PNS Mehran naval base on Sunday night had enough supplies to survive a three-day siege.
"They have enough ammunition and food and they can fight and survive for three days," Ehsanullah Ehsan, a Taliban spokesman, told Reuters news agency.
Speaking to Al Jazeera, Fazal Qureshi, chief editor at the Pakistan Press International news agency in Karachi said: "This operation is probably one of the longest operations which we have seen in Pakistan."
"These people are confined in one particular room, the commandos are advancing so whatever they have they will not be able to use the supplies." Qureshi added.
"They have surrounded and confined the terrorists in one building, some four or five of the terrorists have been already killed."
According to navy officials operation went on for hours because they were trying to capture the fighters alive.
Details of the number of terrorists killed in the operation will be confirmed by a navy spokesperson in a media briefing.
Aaamir Latif, bureau chief, online news network, told Al Jazeera that "Earlier there were reports that the militants had taken hostages but navy sources said that is not the case."
Intelligence officials said that between 15 and 20 attackers were inside the base, and had attacked three hangars housing aircraft.
A military spokesman said two Pakistan Navy staff were killed in the attack.
"One of our officers and one Navy personnel have been martyred," Commodore Irfan ul Haq, a spokesman for the Pakistan Navy, told the AFP news agency. Five explosions were heard at the base ahead of the attack, according to Pakistani Express TV.
Yusuf Raza Gilani, Pakistan's prime minister, condemned the attack.
"Such a cowardly act of terror could not deter the commitment of the government and people of Pakistan to fight terrorism," Gilani said in statement.
Pakistani Taliban claimed responsibility for the attack and threatened further attacks.
"It was the revenge of martyrdom of Osama bin Laden. It was the proof that we are still united and powerful," Ehsan of Taliban told agencies by telephone from an undisclosed location on Monday.
"We had already warned after Osama's martyrdom that we will carry out even bigger attacks," he said, referring to previous vows to avenge the killing of the al-Qaeda leader by US special forces three weeks ago.
Zafar Hilali, a Pakistani defence and foreign affairs analyst, told Al Jazeera that "About five million Pashtuns from north west live in Karachi, it is well known that they have terrorist cells in Karachi, Taliban presence in the city is not surprising."