Vadso Norway
© alamy.comVadso residents can see Russia in the distance on a clear day
A faulty warning siren sparked fears of a late-night Russian invasion in a sleepy Norwegian town just miles from the border.

Frightened locals called the police when the Civil Defence alarm went off in Vadso.

Anxious residents feared a war had broken out when the wailing siren sparked panic just before midnight on Wednesday, the local police force revealed.

Russian troops weren't flooding across the border, but it remained unclear what caused the alarm to go off.

Vadso residents can see Russia in the distance when they look across the Varangerfjord, the easternmost fjord in Russia, within the Arctic Circle.

The town is equipped with multiple Civil Defence sirens, but the only one that sounded around 11.50pm was the one at an old fire station, the public broadcaster NRK reported.

The local police force said it received a number of phone calls from concerned residents who thought they were under attack.

Jan-Olav Schjolberg, a police official, said: "Some believe, of course, the worst, like war."

It took more than 15 minutes for the owner of the old fire station to arrive. Once the building was unlocked, the alarm was located and switched off.

Police have been in contact with the Civil Defence, but there has been no explanation over why the siren went off, NRK reported.

Mr Schjolberg said: "They have to check it out before they can say anything more."

Norway and Russia both have military positions near their northern border.

Vadso, which has a population of about 5,000, is home to a Norwegian military intelligence base.