It’s become common in San Francisco to answer a phone call from a number you don’t recognize, only to hear a prerecorded Chinese-language message you quickly hang up on. But these exact same calls, with the same prerecorded message, are also bombarding people in New York City, Los Angeles, and other cities with large Chinese-American populations.

Designed to lure Chinese immigrants into giving callers money, these automated recordings in Mandarin Chinese are part of a giant, international criminal extortion scheme that has bilked Chinese immigrants across the U.S. out of millions of dollars.

While there are a few variations of the Chinese robocall con, the most common version currently inundating San Francisco is known as the “parcel scam.” The incoming call appears to be from a local number, and a prerecorded male or female voice explains in Mandarin that the Chinese Consulate has an important document that might affect the call recipient’s immigration status.

If the caller stays on the line to connect to a real human being, they are told the parcel is connected to a criminal case involving money laundering. The victim is then informed, in Chinese, that the only way they can avoid arrest is to transfer money to a Hong Kong bank account.

The story is pure fiction, but the financial losses are quite real. Here in the Bay Area, victims have been conned out of an estimated $200,000, according to the San Francisco District Attorney’s office.

“While posing as Chinese officials, these scammers are threatening to arrest victims or their loved ones unless they wire their hard-earned money,” District Attorney George Gascón’s office says in a statement to SF Weekly. “Public education is essential to preventing San Franciscans from falling prey to this cowardly scam.”

The Chinese Ministry of Public Safety estimates that as many as 100,000 people in China and Taiwan are actively engaged in this swindle. The People’s Republic of China Consulate in San Francisco has even gotten involved, condemning the calls, and urging recipients not to comply with the robocallers’ demands.

“All of these phone calls have been proved to be scam traps,” the consulate says. “We would like to restate that the Embassy and Consulates General of China would not ask for personal information, deliver parcel pick-up notices, or ask people to answer inquiries from the police department by way of phone calls. The Embassy would not ask for bank account information.”

Your Caller ID will indicate the robocalls are local, but they’re actually coming from China or Taiwan. The scammers use a tactic called “neighborhood spoofing” to make the call appear to come from the 415 or 510 area code, and the robocalling systems can send out thousands of these calls daily in hopes of catching just one or two victims.

These brute force, mass-robocall strategies are on the increase not just with Chinese scammers, but also with shady American firms claiming to be debt collection or health insurance companies. Call-blocking app YouMail’s Robocall Index estimates that about 3.5 billion U.S. robocalls were made in April 2018, a billion more than in April of last year.

While there is a highly outdated defense mechanism called the National Do Not Call Registry, that doesn’t help much when the calls are coming from countries that couldn’t care less about U.S. law. Sure, you could use a call-blocking app, or manually block each unwelcome call one-by-one. But there are always new ways that scammers — and perfectly legal Fortune 500 companies — stay a step ahead of current technology and regulations to robocall to their heart’s content.

For example, in March, a U.S federal court struck down the definition of what constitutes an autodialer, making it easier for companies to robocall you (and harder for you to sue them). The Trump Administration celebrated the decision, so you can probably expect to see more consumer phone protections dialed back.

If you or someone you know was contacted by a suspicious robocall, report it immediately to the police, the S.F. District Attorney Victim Services Division at 415-553-9044, or the S.F. District Attorney Consumer Fraud Hotline at 415-551-9595.