The London venue, one of the UK capital's biggest tourist draws and best known for housing the Rosetta Stone and the Parthenon Marbles, said police had arrested the suspect.

"An IT contractor who was dismissed last week trespassed into the museum and shut down several of our systems," a museum spokesman said.

"We are working hard to get the museum back to being fully operational but with regret our temporary exhibitions have been closed today and will remain so over the weekend."

Meanwhile in the Netherlands, the Drents Museum in Assen said it was closed for the weekend after robbers used explosives to break in and steal three antique bracelets and a gold helmet.

Police were alerted to an explosion early Saturday, with the thieves stealing the golden helmet of Cotofenesti, dating from the mid-fifth century BC, the museum said on its website.

The helmet -- the centrepiece of a temporary exhibition -- was on loan from Romania's National History Museum in Bucharest.

And in Paris, the world-famous Orsay Museum was forced to disable its own ticketing system for several hours Friday after falling victim to a fraudulent scheme involving "mirror sites", it told AFP Saturday.

The museum, home to works by Vincent van Gogh and other master painters, was alerted Friday that visitors trying to buy tickets online were being redirected without realising it to bogus ticket sales websites.

After suspending online ticketing services for some of Friday, operations were back to normal Saturday, it said.

- 'Further enquiries' -

A spokesperson for London's Metropolitan police said officers responded to the British Museum late Thursday following reports that a man on-site had "caused damage" to its security and IT systems.

Police arrested the man in his 50s at the scene on suspicion of burglary and criminal damage. He has been bailed "pending further enquiries," the spokesperson added.

Part of the museum's permanent collection was also closed Friday following the incident, Britain's Press Association news agency reported.

A message on the museum's website Saturday stated that it was "open but due to an IT infrastructure issue some galleries have had to be closed".

It added this meant "capacity will be limited, and priority will be given to members and pre-booked ticket-holders".

The incident is the latest embarrassing security lapse for the museum after allegations emerged in 2023 that a former employee was suspected of selling items stolen from its vast collection.

About 1,800 objects were disclosed as missing or stolen in August 2023.

The museum dismissed a staff member suspected of involvement in what it called "an inside job", and alerted police who have interviewed a person but made no arrests.

Hundreds of the items have since been recovered.

Following a furore around that scandal, Hartwig Fischer, the director of the museum at the time, resigned.

After a temporary head was appointed, Nicholas Cullinan -- who was previously in charge of the National Portrait Gallery -- took over the role last year.