Islamabad, Sept. 25 (AP): Authorities boosted security at Islamabad’s international airport today after a telephone threat warned that a suicide bomber would attack the facility.

Flights were not affected and more than an hour after the time the caller said the strike would take place, no such attack had occurred, said senior airport security officer Colonel Ashraf Faiz. “The airport is on red alert,” he said. Pakistan has been on edge since a massive truck bomb devastated the Marriott Hotel in Islamabad on Saturday, killing 53 people.