NANJING/LANZHOU, May 22 -- Two flights from Shanghai to Urumqi, capital of Xinjiang Uygur Autonomous Region, continued their journey after clearing security checks at Nanjing and Lanzhou airports.

Low-cost carrier Juneyao Airlines flight HO1229 from Shanghai Hongqiao International Airport to Urumqi was diverted to Nanjing Lukou International Airport after police received a tipoff that a passenger had explosives on board.

All the passengers were searched and nothing was found, according to the police. The flight then took off at 5:50 p.m. and continued on to Urumqi.

Another Juneyao Airlines flight HO1255 with 136 passengers and 11 crew on board from Shanghai to Urumqi was also diverted, this time to Lanzhou, for a police check.

Again, nothing untoward has been found. It continued flight to Urumqi at 9:26 p.m.

An initial investigation by Juneyao Airlines showed that a passenger on flight HO1255 told the flight crew during flight that his companion, who had missed the flight, had phoned him and threatened to blow up the plane. Worried that the luggage he was carrying for his companion may contain explosives, he alerted the cabin crew.

Actually, his companion had switched to flight HO1229 when he missed the flight HO1255, according to the investigation, so both flights were ordered to land for security checks.