JUST IN: Pakistani forces seal off area around Karachi Airport Academy, conduct search operation, reports Reuters witness.
Pakistani forces cordoned off the area around a Karachi airport academy and searched the neighbourhood for militants after the building came under gunfire earlier in the day, a Reuters reporter at the scene said.
Meanwhile, Emirates has advised passengers of possible changes in flight timings for the Dubai-Karachi route in wake of security operations.
READ: Expert warns of more attacks on Pakistan civilian airports
"The shooting came from a nearby shanty settlement towards the ASF (Airport Security Force) academy," said a senior police officer. "Police are launching a search operation now."
Pakistani army sends troops to reinforce Karachi academy
Pakistan's army said on Tuesday it had deployed troops to reinforce security forces trying to protect an airport academy which has come under attack from militants in the port city of Karachi.
"Army troops (have been) moved to reinforce security forces to counter (the) terrorist attack on ASF (Airport Security Forces)," the army's press wing said.
Pakistani spokesman says firefight underway with attackers at airport security training facility.
Dubai flight turns back from Karachi in fresh wave of attack
Flights in and out of Pakistan's Karachi airport suspended
All flights in and out of Pakistan's Karachi airport have been suspended following an attack on a nearby academy run by the airport security force, a civil aviation spokesman said on Tuesday.
"Flights at Karachi airport have been suspended until further notice," the spokesman for Pakistan's Civil Aviation Authority said by telephone.
Second attack in 48 hours
An academy run by the Pakistani airport security force, a unit tasked with protecting Karachi airport, came under fire on Tuesday, Pakistani news channels and a security source said.
"The ASF academy is under attack. There is gunfire. The extent of the damage is not clear," said a senior official at the Federal Investigation Agency. It was unclear who was firing at whom.
This attack comes a day after an all-night siege by the Taliban left 37 dead.
"Gunmen are exchanging fire with Airport Security Force (ASF) personnel at a checkpost guarding the airport," an ASF spokesman said.
TV footage showed paramilitary vehicles and ambulances racing to the scene of the attack.
"We have suspended all flight operations at Karachi airport and we are evacuating passengers," said Mashud Tajwar, a spokesman for Pakistan International Airlines.
The checkpost is located at the entrance of an ASF camp some 500 metres (yards) away from the main airport premises.
The assault came as Pakistan launched air strikes on a militant-infested tribal district, killing 15 people in apparent retaliation for the Monday assault.