Blockchain investigative firm Picshield reports that nearly $4.8 million in cryptocurrency has been moved from cryptocurrency exchange ZB.com amid the exchange's announcement of a suspension of withdrawals.

In a tweet on Wednesday, Beckshield speculated that hackers may be responsible for moving 21 types of tokens from the exchange starting Monday, including Tether (USDT), Shiba Inu (SHIB), and Tesra (TSR).

According to the blockchain investigations firm, the funds total about $4.8 million at the time of this writing, Coin Telegraph reported.

The suspected hack came on the heels of Zb.com's announcement that it was suspending deposits and withdrawals on Tuesday in response to the sudden failure of some core apps. The exchange has warned users not to deposit any cryptocurrency before restoring services.

Many cryptocurrency users have been affected by some of the recent multi-million dollar hacks. In June, an exploit led to the $100 million removal of Horizon Bridge, a cross-chain bridge that facilitated token transfers between the Harmony Blockchain and other networks.

Earlier this week, hackers drained $200 million worth of cryptocurrency from the Nomad Token Bridge.

Users of the cryptocurrency community on Twitter also reported, on Wednesday, that hackers gained access to their funds using an exploit targeting Solana (SOL) wallets.