The shooting took place at the London Pub, which describes itself on its website as “the largest gay and lesbian venue in Oslo.”
“I saw a man arrive with a bag, he picked up a gun and started shooting,” an NRK journalist said in the broadcaster’s report.
A suspect was apprehended nearby, but it is not immediately clear what the motive for the attack was, according to the Reuters report, citing local police.
Three people were severely wounded, police told reporters at the scene.
Oslo is set to hold its annual Pride parade later on Saturday.