PARIS (Reuters) - A French policeman was slightly wounded by a gunshot on Sunday as he tried to apprehend two men who had broken into an Interior Ministry building just outside Paris, a ministry spokesman said.

The circumstance are not clear yet but the most likely hypothesis is a burglary, spokesman Pierre-Henry Brandet said.

Security has been tight in Paris since 17 people were killed in January by Islamist gunmen in attacks on the Charlie Hebdo newspaper and a Jewish shop.

The policeman came upon the two men early in the morning as he was checking on the building in Pantin, northeast of Paris, that included a ministry garage where police cars are parked.

His gun was stolen from him, the spokesman said.

"There was a gun shot, the officer was slightly injured, he is hospitalized," he said.

It was not yet clear why or how the two men had broken into the building or if they were specifically targeting police cars, he said. There is also a police practice shooting stand on the premises, with a small gun room.

The Defense Ministry announced last month plans to reinforce security at its military facilities after a theft of explosives.

(Reporting by Ingrid Melander; Editing by Angus MacSwan)