Oslo: Oslo's Pride march was called off on Saturday after "terrorist" shootings in the centre of the normally tranquil Norwegian capital killed two people and wounded 21 others.
Police arrested a suspect, a 42-year-old Norwegian man of Iranian descent, shortly after the shooting started around 1:00 am (2300 GMT Friday) in three locations in central Oslo, including a gay bar.
"The police are investigating the events as a terrorist attack," police said in a statement.
Organisers of the Pride march that was due to take place on Saturday afternoon said they were calling it off.
"All events linked to Oslo Pride have been cancelled" following "clear" recommendations by police, the organisers wrote on Facebook.
"We do not yet know the reasons for this terrible act, but to all the homosexuals who now are afraid and are in mourning, I say we are all with you," Prime Minister Jonas Gahr Store said on Facebook.
Police said two people had died and 21 were wounded, including 10 seriously, and said two weapons had been seized.
The man arrested "is suspected of homicide, attempted homicide and a terrorist act", senior police official Christian Hatlo told a press conference.
The terror charge comes because "of the number of wounded and killed, the number of crime scenes... and there is good reason to believe that he had intended to sow terror", Hatlo said.
Police received the first reports at 1:14 am and the suspect was arrested five minutes later, police said.
Police said they were able to quickly apprehend the suspect thanks to the "heroic contribution" of bystanders.
The shootings happened near the London Pub gay club, the Herr Nilsen jazz club and a takeaway food outlet.
On Saturday, rainbow flags hung near the scene. Police presence was stepped up throughout the capital.
Norway's anti-terrorist service said on Twitter that it was looking into whether other attacks could be possible but that for the moment "we have no indication of this."
- 'Bleeding man on the ground' -
"He looked very determined about where he was aiming. When I realised it was serious, I ran. There was a bleeding man lying on the ground," a woman who saw the incident told the Verdens Gang newspaper.
"There were a lot of injured people on the ground who had head injuries," another witness was quoted by the paper as saying.
According to an NRK radio journalist present at the time of the shooting, the shooter arrived with a bag from which he pulled out a weapon and started firing.
Police said that the suspect had several minor run-ins with the law, for knife and drug possession.
Norway's King Harald V said in a statement that he was "horrified".
"We have to gather together to defend our values -- liberty, diversity and mutual respect."
Generally peaceful Norway was the scene of bloody attacks on July 22, 2011 when right-wing extremist Anders Behring Breivik killed 77 people.
He first detonated a bomb near the government headquarters in Oslo, killing eight people.
He then disguised himself as a policeman and went on a shooting spree at a summer camp for left-wing youth on the island of Utoya, killing another 69 people -- most of them teenagers.