WASHINGTON- Estonian authorities are investigating the theft of cryptocurrency from users of the country's Atomic Wallet service, a police spokesperson said Wednesday.

More than $100 million in digital assets were stolen from thousands of users of cryptocurrency service Atomic Wallet by a gang of allegedly North Korean hackers known as "Lazarus," cryptocurrency analytics firm Elliptic said Tuesday.

A spokesperson for Estonia's National Criminal Police said in an email that authorities had been investigating the theft since last week but would not be drawn on the details.

Kaarel Kallas said the investigation was still in its early stages "and at the moment we cannot comment on the origins of the attacks."

The FBI, which has in the past investigated Lazarus-linked hacks, declined comment.

Atomic Wallet has not returned messages seeking comment. The service, which says it is headquartered in Tallinn, promises users a higher level of security than typical cryptocurrency exchanges, which have been hit by catastrophic hacks in the past.

"Atomic is Fully Protected," the service's website says.

(Reporting by Raphael Satter Editing by Mark Potter)