1,500 people evacuated from Eiffel Tower after anonymous phone call claimed explosives had been placed around the landmark

French police stand guard near the Eiffel Tower in Paris

Police say the Eiffel Tower has been evacuated after an anonymous caller phoned in a bomb threat.

A Paris police official says nearly 1,400 people have been evacuated following a request from tower operators after the warning Saturday. Police then searched the monument with sniffer dogs for possible explosives, and set up a broad security perimeter.

French authorities have stepped up counter terrorism measures in recent weeks amid heightened concern about threats to France over its military campaign against al—Qaeda—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—metre tower is one of the world’s top tourist attractions, with millions of visitors a year.