Taliban militants attacked a Karachi naval dockyard in a weekend raid which left a Pakistani officer and two insurgents dead, officials said Tuesday.
An officer and six sailors were also wounded in the attack early Saturday on the high security facility, a navy spokesman said, adding that four attackers had been captured alive.
After interrogating the suspects, the navy said in a statement that intelligence agencies had carried out raids to arrest suspected collaborators and accomplices and had recovered "a large quantity of arms and ammunition".
The Pakistani Taliban on Tuesday claimed responsibility for the attack, claiming they had inside help.
"We claim responsibility for the attack on the navy in Karachi," spokesman Shahidullah Shahid told AFP.
"We had support from inside the naval force for this attack. This operation was successful because of this support. We will continue targeting security forces like this in future also," he added.
The Taliban have already threatened a bloody response to a military offensive against insurgents in the North Waziristan tribal region on the Afghan border.
Pakistan's military launched the offensive in mid-June shortly after a brazen attack on Karachi airport that left dozens dead and extinguished a largely fruitless peace process with the Tehreek-e-Taliban Pakistan (TTP).
The weekend raid was the latest in a series of high-profile attacks on key installations by the Taliban in recent years, including an 2011 assault on a naval base, also in Karachi, and on the military's headquarters in 2009.
North Waziristan has become a major base for the TTP, which rose up against the state in 2007, while the United States has long called for action in the area against militant groups targeting NATO forces in Afghanistan.
Pakistan's army says it has killed more than 900 militants and lost 82 soldiers since the start of the operation.