After police cordoned off a large area surrounding the synagogue and sent in a bomb squad, they were able to call of the alarm shortly after 11am.
"The suitcase turned out to be empty. The barriers will remain on Bergstien. Other roadblocks have been removed. No suspect in the case. The case is closed," Oslo Police tweeted.
Police said that the suitcase was set outside the synagogue at around 4am. A bomb squad was called in to investigate the bag and surrounding streets were blocked off. Police did not at any point evacuate the area, which includes a school and a daycare institution.
Police said that video surveillance cameras recorded the person placing the bag at the entrance to the synagogue. The man was described as dark-skinned and dressed in dark clothing.
“The timing and the location are what make us want to investigate the suitcase. We are assuming that there could be anything in that suitcase,” police spokesman Tor Grøttum told broadcaster NRK earlier in the morning.
Michael Grizman, a board member at the Det Mosaiske Trossamfund, thanked police for the "quick reaction".
"The police handled the situation in a good way and all the necessary precautions were taken," he told news agency NTB.
Friday's incident was not the first time that police had to send a bomb squad to the synagogue. In March 2015, a man was seen running out of a building across the street before leaving an item outside of the synagogue. It turned out to be a bag with nothing dangerous inside.
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In September 2006, shots were fired at the synagogue, leading to stepped-up patrols in the area.