Oslo's central train station was briefly evacuated and a bomb disposal team deployed on Wednesday morning because of a suspicious item of baggage found on a bus, officials said.
"Nothing suspicious was found and all security cordons have been lifted," Oslo police said in a statement after inspecting the scene.
"We inspected the entire bus with bomb-sniffing dogs and robots and did not find anything," an unnamed policeman at the scene told TV2 television channel.
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The policeman said earlier that a man was seen leaving "in a strange way" a bus parked in front of the station and that a suitcase was found "strangely" in the aisle aboard the bus.
Norway is on the alert after twin bombing and shooting attacks on Friday left 76 people dead, the worst bloodshed in the country since WWII.
"It's normal, the police are on the alert. We're not afraid but we're being careful," medical assistant Randi Roe told AFP as she waited for the police cordon to be lifted.
A railway official earlier identified the bus as the shuttle temporarily replacing the train service to Oslo airport.
An AFP journalist said police had sealed the station entrance, with around 10 police vehicles and three fire engines on the scene.
Around 200 people had been waiting with their bags outside the station.
