Agencies: Two people were killed and 21 were injured, including 10 in critical condition, in a shooting last night at a gay nightclub in the center of the Norwegian capital Oslo, according to the police who said the perpetrator of the attack is Norwegian of Iranian origin. The attack was also described as a "radical Islamic terrorist act." Al Jazeera's correspondent in Oslo reported that Norwegian intelligence raised the security threat level from normal to exceptional following the attack.

Police operations chief Tori Barstad told the "Aftenposten" newspaper that the shooting took place at the "London Pub," a popular gay club in the heart of Oslo, and extended to an adjacent club and a nearby street where the suspect was arrested a few minutes after the shooting began.

The police announced that the shooter is Norwegian of Iranian origin.

Christian Hatlo, a police official in Oslo, said at a press conference that the suspect – whose identity was not disclosed – is known to the domestic intelligence service responsible for counter-terrorism. He is also known to the police for minor offenses such as carrying a knife and has been convicted for drug possession.

Al Jazeera's correspondent said the accused shooter was charged with murder, attempted murder, and terrorist activity.

Norwegian network "NRK" quoted the police saying they are investigating whether the shooting is linked to terrorism. They said at least two people were killed and 21 others injured in the incident.

The gay nightclub is located on a popular street in central Oslo, and "Aftenposten" newspaper quoted the police as saying that civilians helped in apprehending the suspect.

An annual gay festival was supposed to take place in Oslo this Saturday but was canceled.

Earlier, "NRK" quoted the police operations chief saying that "10 people are receiving medical aid," adding "3 people are seriously injured" and stating that all evidence points to a single attacker.

The same network quoted journalist Olaf Rønnberg as saying he saw "a man with a bag, pulled out a rifle, and started shooting."

The police provided no information about the age or identity of the arrested suspect who has not made any statements. The police searched his apartment and confiscated two weapons used in the attack, according to the network quoting Barstad.

According to "NRK," there are 3 crime scenes, without clarity if this refers to 3 different locations.

Photos published by "VG," "NRK" and other media showed a large gathering of emergency personnel outside the "London Pub," including police and ambulance crews. Helicopters hovered over central Oslo while sirens from ambulances and police vehicles were heard throughout the city.

On another note, Canadian Foreign Minister Mélanie Joly condemned the incident, describing it as a horrific event.

Joly expressed solidarity with the LGBTQ community targeted in the incident and said in a tweet on Twitter this Saturday morning, "Deeply horrified by the deadly attack against the LGBTQ2I community in Oslo."

She added, "My heart is with the families of the victims, and the queer community and the Norwegian people can be sure of our solidarity."

Joly concluded her tweet by saying, "The fight against terror unites us."