(Reuters) - Federal prosecutors in Manhattan charged cryptocurrency exchange KuCoin on Tuesday with violating U.S. anti-money laundering laws, allowing billions of dollars in illicit funds to be transferred since its founding in 2017.

Seychelles-based KuCoin is one of the world's largest cryptocurrency exchanges. Prosecutors said the exchange sought business from U.S. customers without registering with the U.S. Treasury Department and putting in place procedures to verify clients' identities as required by U.S. law.

A spokesperson for KuCoin did not immediately reply to a request for comment.

Prosecutors also charged the exchange's founders, Chinese nationals Chun Gan, 34, and Ke Tang, 39, with conspiracy. They remain at large, according to prosecutors.

The U.S. Commodity Futures Trading Commission separately filed a civil lawsuit against KuCoin alleging it failed to register its futures and swaps activities with the regulator.

KuCoin in December agreed to block New York users from its platform and pay $22 million to settle the state's lawsuit accusing it of failing to register there.

KuCoin trails Binance, Coinbase and Kraken among cryptocurrency spot exchanges on factors including traffic, liquidity and trading volumes according to the data company CoinMarketCap.