The U.S. Treasury Department has officially accused the North Korean hacking group Lazarus of stealing $625 million in cryptocurrency from the Ronin network, the blockchain powering the popular play-to-earn cypto game Axie Infinity, Vice reported Thursday.

Developer group Sky Mavis, which owns the Ronin network, says the FBI concurs.

"We are still in the process of adding additional security measures before redeploying the Ronin Bridge to mitigate future risk," the company wrote in a statement. "We expect to deliver a full post mortem that will detail security measures put in place and next steps by the end of the month." It expects to bring its bridge, which allows users to transfer funds between other blockchains and Axie Infinity, back online in the same timeframe.

The Axie Infinity heist took place in late March, instantly becoming one of the biggest crypto heists to date.

The Treasury Department has added the wallet address that received the stolen funds to its list of sanctions, and attributed the wallet to the Lazarus group. It currently contains over $445 million USD in the form of 148,000 Ethereum. It sent nearly $10 million (3,302.6 ETH) to another address Wednesday.

Lazarus has ties to North Korea's intelligence agency and perpetrated at least seven attacks last year, according to the cryptocurrency investigation group Chainanalaysis. It's said to have been responsible for the Sony Pictures hack in 2014 that leaked the Seth Rogen and James Franco comedy "The Interview," which was set in North Korea.