PARIS (AP) — The Eiffel Tower was evacuated Saturday night after an anonymous caller phoned in a bomb threat, police said.

Nearly 1,400 people were sent away from the tourist attraction following a request from tower operators after the warning, a Paris police official said. Police then searched the monument with sniffer dogs, and set up a security perimeter.

No explosives were found and the site was to be reopened, the official said on condition of anonymity because she wasn't authorized to speak publicly.

French authorities have stepped up counterterrorism measures in recent weeks amid heightened concern about threats to France over its military campaign against al-Qaida-linked fighters in Mali which began more than two months ago.

The tower is occasionally evacuated because of such warnings — at least once last year and twice in 2011. The 324-meter (1,063-foot) tower is one of the world's top tourist attractions, with millions of visitors a year.