The American branch of Binance, the giant cryptocurrency exchange, said late on Thursday that it would no longer allow customers to trade on its platform using U.S. dollars, after its banking partners cut the firm off in response to a crackdown by federal regulators.

The move is a major blow to Binance.US, the American arm of the world’s largest crypto exchange. One of the main functions of an exchange is allowing users to convert their traditional money into digital currencies like Bitcoin or Ether. Binance will no longer be able to offer that service in the United States.

In a message to customers, Binance.US said it was “taking necessary actions as we transition to a crypto-only exchange.” In recent days, the company said, its banking partners had signaled that they would no longer facilitate the movement of dollars on and off Binance.US’s platform.

The Securities and Exchange Commission sued Binance on Monday, accusing the firm and its chief executive, Changpeng Zhao, of mishandling customer funds and lying to regulators. In a separate filing, the S.E.C. asked a federal judge in Washington to freeze assets related to U.S.-based customers of Binance, citing “the defendants’ years of violative conduct.”

Representatives for Binance did not immediately respond to a request for comment.

The crypto industry has been under intense pressure from federal regulators since November, when the collapse of the FTX exchange set off an industrywide crisis. The day after it sued Binance, the S.E.C. filed a separate case against Coinbase, the largest American crypto exchange. Some crypto companies have vowed to fight the crackdown, while others are making plans to leave the United States entirely.

In its message to customers on Thursday, Binance.US said it was facing “extremely aggressive and intimidating tactics” from the S.E.C. The company said it was suspending deposits of U.S. dollars and urged users to withdraw any dollars they have been storing on the exchange by Tuesday.

At the same time, the company tried to assure its customers that their savings were backed up by money it holds in reserve.

“To be clear, we maintain 1:1 reserves for all customer assets,” the message said. “Customer funds are always safe, secure and available.”