The Eiffel Tower in Paris has been closed 'until further notice' after a man was spotted climbing up it.
According to reports, police have arrived at the scene and are negotiating with the man.
A statement posted to the official Eiffel Tower Twitter account said: "The tourEiffel is currently closed until further notice.
"To avoid too long a wait, we advise our visitors to postpone their visit."
A representative told the Irish Independent that the man had paid entrance to the tower. He then began to climb at the second level, which sits at 149m.
The Irish Independent's Deputy News Editor Claire Murphy tweeted: "Some kind of security incident at the Eiffel Tower. We are at the top and not allowed to leave. Reports that someone is climbing the tower. Anyone know anything?"
In a later tweet, Murphy added: "We are being told a guy paid in and then started to climb from the second floor #EiffelTower."
The incident began at approximately 2:15pm local time.
The Eiffel Tower Twitter account has said visitors who had already purchased a ticket will be able to get a refund, saying: "Please send to our customer service: [email protected] a mail explaining the situation + copy/photo of your ticket(s). Customer service will handle this situation.
"We are sorry for the inconvenience."
Last week, France celebrated the 130th anniversary of the Eiffel Tower's public opening in 1889 - marking the milestone with a laser light show that retraced the monument's history.
Designed by Parisian engineer Gustave Eiffel and built for the 1889 Universal Exhibition, the structure rises 324m above the French capital.
It has become one of the most popular tourist attractions in the world, with around 6 million people ascending the landmark every year.
It was the world's tallest building in the world until 1929, when it was dethroned by the Chrysler Building in New York City.