A bomb threat has forced a Pakistan International Airlines plane to land in Turkey.

Turkey's state-run Anatolia news agency says the jet carrying 378 passengers was on its way to Britain Wednesday, when it made an emergency landing at Istanbul's Ataturk Airport.

The plane was evacuated and security officials with sniffer dogs searched the aircraft.

The flight began in Islamabad and was on it way to Manchester.

Turkish state-run media say the Boeing 777 received a bomb alert while flying over Sofia, the capital of Bulgaria.