This is reported by NRK with reference to the head of the police security service Marie Benedict Bjornland.
According to the newspaper, the suspect attacked the girl in the store.
It is noted that the victim is in critical condition.
Norwegian intelligence agencies are checking the version of the attack.
“I cannot go into details, but he stated that he was planning a terrorist attack and wanted to kill more people,” said Bjornland.
Earlier it was reported that FBI agents arrested a citizen of Russia Dmitry Makarenko in the city of Saipan in the Northern Mariana Islands.