Rare security breach at Tower of London

LOCOG chair Seb Coe (second from right) and Rio Tinto chairman Jan du Plessias (second from left) pose with the medals as official metal supplier for the Olympic Games Rio Tinto hands over Olympic and Paralympic medals to LOCOG for secure storage in the vaults at the Tower of London on July 2, 2012 in London, England. Photo by Andrew Redington/Getty Images

LONDON A rare security breach has been reported at the Tower of London, one of the British capital's most famous landmarks.

A spokesperson from the Historic Royal Palaces told CBS News that the incident occurred in "the Tower environs and the intruder did not gain access to the Tower itself."

Authorities say the Crown Jewels and other unique artifacts are safe but that locks had to be changed after an intruder broke in and stole some keys.

Officials said Monday the keys were stolen from a sentry box at the site. They would have provided access to the Tower's drawbridges and some other areas.

"It would not have been possible to gain access to the Tower with any of these keys and at no point was the security of the Tower at risk," the spokesperson told CBS News.

Authorities say the keys were stolen last Tuesday and a police investigation into the theft is under way.

A Historic Royal Palaces statement said security procedures had not been properly followed.

The Tower is guarded by Yeoman Warders, commonly known as Beefeaters.