Norway police investigate explosion in central Oslo

OSLO (Reuters) -Norwegian police said on Tuesday they were investigating a blast in central Oslo and warned people to stay away from the location as there were likely more explosives present.

There were no report of injuries at the site, located in the immediate vicinity of a university campus and some 500 metres (yards) from the royal palace and the Israeli embassy.

In a rare step, authorities sent an emergency message to Oslo residents' mobile phones, warning them about the blast.

"There has been an explosion in the area (called) Pilestredet. Given that there is still an explosive device in the area, the police wish that people stay away from windows," the message said.

"As of now, we are not evacuating the area."

The incident comes nearly a day after reports of drone sightings near Oslo's and Copenhagen's airports.

(Reporting by Nerijus Adomaitis and Gwladys Fouche, editing by Terje Solsvik)