A Swedish police officer has been stabbed in the neck in a busy square in Stockholm.

Officials have said it was an unprovoked attack at Medborgarplatsen Square and that the knifeman has been arrested for attempted murder.

The attacker is said to have crept up behind the police officer before delivering a blow to the neck at around 10.30am this morning.

A man with blood-stained jeans is dragged away by two police officers as horrified residents look on

Heavily armed specialist officers descend upon Stockholm after the attack on the police officer

A police officer carrying an assault rifle talks to a member of the public during the lockdown of Medborgarplatsen Square

The attacker is apprehended by a police officer as half a dozen colleagues spring into action

Three police officers carefully comb for evidence after one of their colleagues was stabbed

Police immediately locked down the area and witnesses described a man aged around 30 being dragged away.

A witness told Aftonbladet: 'I got up from the subway when the police dragged a man, he appeared to be at the age of 30.'

The injured policeman was rushed to Karolinska Hospital but the extent of his injuries are unknown at the moment.