By Tom Miles
GENEVA (Reuters) - Police tightened security at Geneva's Cointrin airport on Wednesday after a French tip-off about a possible bomb threat.
Preventive security measures were being taken around the airport, Geneva police said on their Facebook (NASDAQ:FB) page, and would continue for an indefinite period.
Officers armed with machine guns were on duty around the airport, which straddles the Swiss border with France.
"We have received information that is serious enough to put in place preventive controls here at Geneva airport. We cannot give details of staffing numbers, nor on the information we have received, for obvious reasons of security," a Geneva canton police spokeswoman said. "The investigation is indeed being conducted by the French authorities for the time being."
Airport officials said an alert was triggered by an anonymous telephone call, without giving further details. A security source said it was a bomb threat.
The heightened security closed most airport entrances. Armed officers were checking the documents of visitors but airport officials said the airport was open and functioning normally.
Airport spokesman Bertrand Staempfli advised passengers to arrive early because of the extra checks but said there were no serious problems with access.
Security was also heightened on the French side of the border. France itself is on high alert after a series of Islamist militant attacks, including the killing on Tuesday of a Catholic priest during a church service in northern France by knife-wielding assailants.
The Tribune de Geneve paper said one of the assailants in that case was arrested at Geneva airport last year while trying to travel to Syria and was later extradited to France.