The U.S. government said on Tuesday that telecom “gateway providers” appear to be doing a better job blocking scam-oriented international robocalls from reaching Americans.

The Federal Communications Commission (FCC) said its efforts with the Federal Trade Commission (FTC) “reduced apparently illegal robocall traffic across multiple networks.” The two agencies reached out last year to seven major gateway providers — companies that serve as “on ramps” for international calls to the U.S. — urging them to do more to cut down potentially fraudulent voice-call spamming.

The agencies said Tuesday that since then, they have seen “a decrease in the volume” of problematic robocalls. The measuring stick was the “tracebacks” sought by law enforcement, as reported by the Industry Traceback Group, which is run by a telecom trade association.

“Law enforcement entities and others typically initiate tracebacks to identify the source of suspected illegal calls, and a decrease in tracebacks pointing to a specific provider may be an indication of reduced illegal traffic,” the FCC said.

Last year the Biden administration warned gateway providers that failing to do more to authenticate the sources of calls could result in the FCC ordering networks in the U.S. to block their traffic. Gateway providers typically handle voice over internet protocol (VoIP) calls.

“Illegal robocalls are a scourge that waste Americans’ time and defraud them of money. VoIP providers knowingly enable these scammers, allowing robocalls to proliferate on a massive scale,” FTC Chair Lina Khan said in a statement. “The FTC will continue to crack down on upstream actors that facilitate fraud, and we’ll keep working with the FCC to protect Americans in the fight against illegal telemarketing.”

The FCC’s Robocall Response Team didn’t provide detailed data about the reduction in apparently illegal calls, but claimed it had made significant headway in phone scams involving fake auto warranties, student loan programs and high-interest mortgages.

The seven gateway providers contacted by the FCC and FTC were: Acrobat Communications, which operates as Telstar Express; Bandwidth; CenturyLink; iDentidad Advertising Development; the U.S. arm of Tata Communications; Telco Connection; and TeleCall Telecommunications.