The Louvre museum and the Palace of Versailles were evacuated and closed on Saturday after receiving attack threats. France is on its highest security alert after a teacher was stabbed on Friday.

Two of Paris' biggest and most famous tourist attractions were cleared and closed on Saturday in response to attack threats.

Around 15,000 visitors were requested to leave the Louvre in central Paris after the museum "received a written message stating that there was a risk to the museum and its visitors," a museum spokeswoman told French news agency AFP.

She didn't initially elaborate on the precise nature of the threat but French broadcaster BFMTV cited police sources who said the museum had received "bomb threats."