An explosion at a residential building in Monaco has injured three people, two of them critically, according to French media.

The blast reportedly occurred around 21:00 local time (19:00 GMT) after a bag was left outside the building on Rue Révérend Père Louis Frolla, near the border with France.

Minister of State Christophe Mirmand told AFP it was “very likely an attack” and police were investigating.

He said the blast had been caused by an explosive device which appeared to contain bolts and pellets.

“This is the first time in history, to my knowledge, that such an act has taken place in the principality,” Mirmand, the head of Monaco’s government, said.

Police and emergency personnel were deployed to the scene.