Sweden’s main airport, Stockholm Arlanda International Airport, was evacuated following a bomb threat.

Two of the three gates at a terminal were evacuated by 10.30am on Tuesday after the Stockholm police discovered a bomb threat at 8.50am.

Arlanda International Airport released a statement on its website saying: "Due to suspicions concerning a luggage, two of the piers (Gates 1-10 and 11-24) in Terminal 5 have been evacuated.

"It’s not the first time we’ve received this kind of threat but it is not very common."

"Travellers on site are referred to other parts of the terminal and are asked to listen to the loudspeaker announcements and also to follow the information given on information boards in the terminal. Air traffic is running but the event is expected to cause delays. Road and rail service to the airport is operating as usual."

While some media houses reported that there were threats to two planes, the Local quoted Lars Byström from Stockholm police as saying that the threat was against only one plane.

"My information is that it involves one plane," said Byström.

"We have not yet spoken publicly about the nature of the threat. Officers are at the scene and the security operation is ongoing. It’s not the first time we’ve received this kind of threat but it is not very common."

Reuters quoted police as saying that it had seized but not arrested an apparently mentally instable man after he made a bomb threat to an airplane. Police lifted the cordons at the airport following a search at the airport gate and moved the plane to finalise a search.

Airport operator Swedavia said on its website that flights at Arlanda, which is situated north of the capital, were resuming but warned against delays throughout the afternoon.