Troops have ended a siege by militants who attacked a naval base in the port city, navy sources say.
The troops are now said to be "mopping up" after the raid, which has left at least 12 soldiers dead, reported the BBC.
Fierce gunfights raged overnight as heavily-armed terrorists stormed a Naval Base here, destroyed two surveillance aircraft and left seven personnel dead.
Dysfunctional Tehrik-e-Taliban Pakistan (TTP) accepting responsibility for the attack on Karachi Naval Base have said that they have avenged the killing of Osama Bin Laden adding that their fighters have enough ammunition and food to last three days.
On Sunday night at around 10:30 pm gunmen armed with rockets and explosives stormed a naval air base PNS Mehran destroying two US-made surveillance aircraft and killing seven personnel.
It was the worst assault on a military base since the GHQ was besieged in October 2009 in Rawalpindi
According to media reports, up to 20 militants crept into the base from three sides under the cover of night late Sunday, triggering gun battles and a series of explosions. Twelve hours later, officials said they were still battling to restore order.
By mid-morning, fire crews had doused towering flames over the PNS Mehran, a base of the Navy's air arm in the teeming port city of Karachi.
Interior Minister Rehman Malik said the "terrorists" sneaked into the base from three points adjacent to residential areas.
"A (single-storey) building in the premises is still under their occupation from where they are exchanging fire with our soldiers," Malik told reporters.
"It is not just an attack on a Navy establishment, it is an attack on Pakistan," Malik added, warning that those who sympathies with the Taliban and al Qaeda should instead "join hands with us to save our country".
A spokesman for the TTP, who have stepped up attacks to avenge the May 02 death of bin Laden, claimed to have dispatched 15 to 20 suicide bombers equipped to fight for a week.
"We had already warned after Osama's martyrdom that we will carry out even bigger attacks," TTP spokesman Ehsanullah Ehsan said from an undisclosed location.
"Our people present inside are all fedayeen (suicide bombers). They are 15 to 20 in number and were sent after proper planning. They can fight for one week and until they embrace martyrdom," he said.