The two men were known to police and face charges of "complicity in an act of terrorism".
Two more suspects have been arrested in connection with a deadly shooting during the annual LGBTQ Pride festival in Oslo.
Norwegian police confirmed on Monday that two more suspects — both from Oslo — had been detained. They face preliminary charges of "complicity in an act of terrorism".
Two people were killed and more than 20 others injured in the shooting on 25 June in the nightlife district of Norway's capital.
A total of four suspects have now been arrested, including the suspected gunman, a 43-year-old Norwegian citizen of Iranian origin.
The two latest suspects — a man in his 40s with Somali citizenship and a Norwegian national in his 30s — were arrested on Sunday and were known to the authorities.
On Friday, Oslo police also announced that they had issued an international arrest warrant for a 45-year-old "Islamist", who they believe is in Pakistan.
"To ensure the best possible cooperation with the Pakistani authorities, we had Oslo police officers in Pakistan a short time ago," a police spokesperson said.