A security academy at Karachi's airport came under attack on Tuesday, less than 48 hours after an all-night siege by Taliban gunmen at Pakistan's busiest airport that killed more than 30 people.
"The ASF academy is under attack. There is gunfire," a senior official at the Federal Investigation Agency said, referring to the Airports Security Force.
It was not immediately clear who was behind the latest strike. A Reuters correspondent near the airport of Pakistan's commercial capital heard gunfire and saw at least four ambulances rushing to the scene.
The army said it had deployed troops to the scene where, according to a Pakistani television report, three militants had been surrounded by security forces.
All flights in and out of the sprawling city of 18 million were suspended, an official said.
Ten Taliban militants disguised as security force members and armed with rocket-propelled grenades stormed the airport on Sunday night, one of the most brazen attacks in a long-running Pakistani Taliban insurgency.
The assault destroyed prospects for peace talks between the Taliban and the government of Prime Minister Nawaz Sharif and triggered speculation that the army might opt for an all-out offensive against militant strongholds.
Earlier on Tuesday, Pakistani fighter jets bombed Taliban positions on the Afghan border.
"Nine terrorist hideouts were destroyed by early morning military air strikes near the Pakistan-Afghan border," the army's press wing said, adding that 25 militants were killed.
Seven more bodies
It was unclear if the latest air strikes signalled the start of a broader offensive in the North Waziristan region where the al Qaeda-linked Taliban are based, or indeed if they had been carried out in retaliation for the airport attack.
The air force has periodically conducted raids to bomb Pakistani Taliban positions in the lawless, ethnic Pashtun region but has yet to launch a major offensive.
The semi-autonomous Pashtun lands along the border, known as the Federally Administered Tribal Areas, have never been brought under the full control of any government.
The Pakistani Taliban, an alliance of insurgent groups fighting to topple the government and set up a Islamist state, said they had carried out the late Sunday attack in Karachi in response to the air strikes on their strongholds.
At Karachi's airport, rescue workers earlier recovered the bodies of seven people trapped inside a cargo building, bringing to 34 the death toll from the first assault.
"The bodies are badly charred beyond identification," said a morgue official who declined to be identified.
Airport officials said the victims had taken refuge in the cargo shed to hide from the gunfire but got trapped when the building caught fire at the height of the battle.
"They (security forces) were busy killing militants and clearing the area, nobody bothered to rescue these trapped men," said Abdul Rehman, whose brother was among those killed. "They could have been saved if timely rescue efforts had been made."