ISLAMABAD - Pakistan Air Force (PAF) Monday scrambled fighter jets over several major cities as a sign of enhanced vigilance following mounting tension between India and Pakistan after the Mumbai attacks. "In view of current environment PAF has enhanced its vigilance," PAF said in Press release issued here on Monday. Residents in Islamabad, Rawalpindi and Lahore made panicked telephone calls to media outlets to ask about the low-flying fighter jets. Two civilian flights were delayed due to the exercise of PAF, an airline official said. "Two of our flights were delayed for some time because of PAF exercises," PIA official spokesman Muhammad Latif said while dismissing television news channel reports of a high alert at Pakistani airports. The flights were delayed at Lahore airport. Agencies add: Pakistan Air Force has been put on red alert amid mounting tensions between Pakistan and India after Mumbai attacks. Reliable sources of Defence Ministry informed Online that PAF fighter planes flew over major cities including Muzaffarabad and LoC with a view to cope with any untoward incident thus checking their operational capabilities in this regard. PAF spokesman Hamayun Waqar Zafar was of the view that PAF fighter planes were involved in routine flights, making it clear that there is no need of any sort of panic or fear. In view of current environment, PAF has enhanced its vigilance, he said. He further made it clear that PAF is fully committed and determined to give a befitting response to the enemy. Meanwhile, a high level meeting under Joint Chief of Staff Committee General Tariq Majeed was held here on Monday. Sources say a host of issues concerning national security came under discussion during the meeting. Gen Tariq took in confidence the military leadership on various matters including his recent visit to China, sources said.