A manhunt is under way for a gang of thieves who carried out a broad daylight raid on Paris’s Louvre Museum and stole jewels described as priceless.

French Interior Minister Laurent Nuñez said it took just a few minutes for the masked suspects to carry out the robbery on Sunday morning, shortly after the museum opened to visitors.

The gang appear to have used a mechanical ladder to gain access to a first-floor window, before smashing through display cases and escaping on scooters.

Officials have not confirmed which items were taken but the gallery which was targeted is home to France’s royal jewels.

The theft led to the evacuation of the Louvre, which remained closed throughout Sunday.

The jewellery was stolen from the Galeria d’Apollon (Gallery of Apollo) at around 09:30 local time (08:30 GMT), the French interior ministry said.

French media reported that the thieves used small chainsaws to gain access to the building. A government minister said three or four people were involved.

A vehicle-mounted extendable ladder was seen leading up to a window a stone’s throw from the River Seine, apparently having been left behind by the gang.

No one was injured in the incident.

France’s Culture Minister Rachida Dati said one item had been found close to the museum, seemingly dropped during the getaway.

Several French media outlets reported it was a 19th century crown belonging to Empress Eugenie, adding that it had been broken.

According to the Louvre’s website, the ornate crown features golden eagles and is covered in 1,354 diamonds and 56 emeralds.

Beyond their commercial value, Nuñez said the stolen items have a cultural and historical value that could not be calculated, describing them as “priceless” and “of immeasurable heritage value”.

Police were seen turning tourists away from the museum, the world’s most visited, throughout Sunday as people continued to arrive oblivious to the closure and investigation.

American tourists Jim and Joan Carpenter said they were about to see Leonardo da Vinci’s Mona Lisa when security guards “swept us out of the gallery”.

The couple was ushered past the Galeria d’Apollon and out through an emergency exit, Mrs Carpenter told Reuters news agency.

Mr Carpenter said there was “lots of confusion” in the museum, and guards told the couple there were “technical difficulties” when they asked what was going on.

“I knew something was up because of the way they swept the whole museum,” Mrs Carpenter said.

Mr Carpenter added: “But it’s great. This is our last day of a long trip and it’s the most exciting part today.”