Air traffic controllers in Jakarta received the threat through a call on Saturday from an unidentified person claiming that the plane flying route SV5688 from Jeddah to Surabaya would explode. At the time, the plane was flying above Aceh, Indonesia’s westernmost province.

The threat forced the pilot to immediately divert the flight and make an emergency landing at Kualanamu International Airport, just outside Medan, the capital of Aceh’s neighbor North Sumatra.

None of the 376 passengers or 13 crew members on board were injured during the emergency landing.

A search by the Indonesian Military (TNI) and the police bomb squad did not turn up any suspicious objects and the plane was declared safe, North Sumatra Police chief Insp. Gen. Whisnu Hermawan Februanto told a press conference on Saturday.

All the passengers were flown to their destination at Juanda International Airport in Surabaya in the early hours of Sunday.

Authorities said the person behind the threat has yet to be identified because they used a virtual private network (VPN), making the call difficult to trace.