The threats were received after the flights operated by the state-owned air carrier had taken off Wednesday from Lahore, one bound for Manchester, England, and the other for Kuala Lumpur, Malaysia, airport authorities said.
The Manchester-bound Boeing 777, with more than 340 people aboard, was diverted to Istanbul, the Daily Times reported. The Malaysia-bound A310, carrying 162 people, landed safely at Kuala Lumpur International Airport, the Pakistani newspaper said.
The report said the bomb threats were contained in an e-mail received at the airline's cargo center. Details of the threats were not available.
An airline spokesman said both planes were searched using sniffer dogs after landing.
Pakistan's News International quoted the Turkish media as saying the bomb alert was received by the Manchester-bound flight as it flew over the Bulgarian capital of Sofia, and the plane then landed at the Istanbul airport, the closest facility.