Oslo's central train station was partially evacuated for hours Wednesday morning, after police received reports of a suspicious suitcase.
A man dressed in dark clothes and wearing a white cap reportedly left a dark blue suitcase in one of the buses the railway authorities have been using to shuttle passengers from and to the railway station, which is under reconstruction.
The driver of the bus, who saw the man take out his mobile phone and leave the bus at a fast pace, immediately informed the railway authorities NSB after an American passenger saw the suspicious suitcase. There were between 15 and 20 people on the bus.
The police retrieved the suitcase with a robot, but found nothing suspicious in it, local broadcaster NRK reported. They also used sniff dogs to search the bus and the surrounding area but found no explosives.
Norway is on high alert after Friday's twin attacks, which altogether claimed 76 lives in a downtown explosion in Oslo and a shooting rampage in the Utoeya island later the same day.
The Oslo district court had order an eight-week pretrial detention for 32-year-old, who confessed in a Monday court hearing to both deadly attacks, to facilitate investigation.
Police and prosecution were considering whether Breivik could be charged with crimes against humanity, the maximum sentence for which is 30-year imprisonment.