A Dubai-based platform allegedly moved millions through a sprawling network, drawing scrutiny from Washington and regulators far beyond the United States.

On Friday, the United States imposed sanctions on the unlicensed interstate cryptocurrency exchange Shelbit, which, according to U.S. authorities, processed millions of dollars in cryptocurrency for elite units of Iran’s Islamic Revolutionary Guard Corps (IRGC) and other entities linked to the Iranian government.

According to a Reuters investigation published on July 31, Shelbit, based in Dubai, became the hub of a roughly $4 billion sanctions-evasion scheme. The investigation indicates that the exchange transferred cryptocurrency from Iran’s central bank, as well as to…