COPENHAGEN(REUTERS) - A spate of bomb threats in Denmark forced the evacuation of two provincial airports and two shopping malls on Monday (Oct 17) and briefly closed a university campus in Copenhagen, police said.

It was unclear who was behind the threats.

Additional threats were sent to other locations in the capital area, including Copenhagen Airport, but were deemed hoaxes partly because they were all from the same sender, the police told Danish broadcaster TV2.

"There have been a number of bomb threats in a short period over the whole country," Danish police said on Twitter.

The Copenhagen Business School was briefly evacuated but allowed students back after checks, according to the newspaper Ekstra Bladet.

An airport outside Roskilde, a province about 35km from Copenhagen, was evacuated at midday as well as RO's Torv, a shopping mall in central Roskilde, police said.

A shopping mall in Slagelse, near Roskilde, was evacuated along with a domestic airport in north-east Denmark.

"It wasn't chaotic or hectic, but there was this feeling of apprehension," Anton Bestle, an eyewitness who was evacuated from RO's Torv, told Reuters.