LONDON — British police were hunting a gang who raided safety deposit boxes in London's jewelry district, making off with cash and gems in what local media said could be the country's biggest-ever heist.

London's Metropolitan Police said the thieves used heavy cutting equipment to get into the vault at Hatton Garden Safety Deposit Ltd, where they are believed to have broken into 60 to 70 boxes.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

According to The Sun newspaper, the gang are thought to have tunneled their way in through one wall to access an elevator shaft at the building on Friday, while businesses in Hatton Garden — home to almost 300 diamond, gold and gem dealers and more than 50 shops — were closed. They then rappelled down to the vault and smashed their way in, an unnamed source told the paper. NBC News was unable to independently verify the report.

Police gave no details of what was stolen but the Sun said the haul could be as much as 200 million pounds ($300 million), dwarfing the amounts taken in Britain's previous big heists.

On its website, Hatton Garden Safe Deposit Ltd said it was founded in 1954 and was one of the first companies in Britain to offer safe deposit boxes. "We are currently one of London's most successful and leading safe deposit companies aiming to provide our clients a secure and cost-effective solution to store and protect important and irreplaceable personal belongings," it said.

IN-DEPTH

— Reuters