President Donald Trump communicates to America directly, with tweets from the iPhones that don’t leave his side. And China is likely listening in.

“We briefed his chief of staff early in 2017 about the vulnerabilities of these phones,” said a frustrated former senior intelligence official. “It scared the crap out of Reince Priebus but that didn’t matter. It didn’t change the behavior of the president.”

The New York Times reported Wednesday that Trump is still using those vulnerable phones, and Beijing and Moscow are listening in on the president’s calls from “human sources inside foreign governments and intercepting communications between foreign officials.”

That’s exactly what intelligence officials feared when they first briefed the tech-reliant commander-in-chief’s staff, the former official said, speaking on the condition of anonymity to discuss the sensitive briefings.

Cyber experts have long warned of the vulnerability of cellphones to interception especially via WiFi, when the hacker can ride the signal into the phone and plant a program that turns the phone into a recording device—just one of many ways a standard cellphone can be compromised.

“Communications over commercial cell service can be intercepted and listened in on. It takes specialized equipment, but any country or criminal group could do it,” said Bob Gourley, former chief technology officer for the Defense Intelligence Agency. “You have to assume that 100 percent of the embassies in D.C. are striving to collect what they can.”

“It’s far from a secret that cellular phone calls bouncing off towers are interceptable,” said Todd Rosenblum, a former intelligence official whose past posts include Homeland Security deputy undersecretary of Intelligence. “The fundamental issue is that the president is not willing to adhere to the most basic norms of telephony operational security.”

He added: “The Chinese and Russians can and do augment what they learn about his emotional state and priorities in his tweets with more specific data spilled during unprotected cellular phone calls.”

Trump has two iPhones the National Security Agency has altered to make safer, similar to the one they created for President Barack Obama, but Trump continues to use his personal iPhone because his contacts are in it, the Times reported.

The report, which The Daily Beast has not confirmed, said Beijing is targeting friends of Trump like Blackstone Group chief executive Stephen A. Schwarzman and Las Vegas casino magnate Steve Wynn through Chinese business contacts, seeking to sway Trump’s China policy.

“There’s no question that nefarious state actors are targeting the phones of everyone in government. That’s what the Chinese OPM hack taught us,” said former CIA officer Dan Hoffman, referring to the massive data breach of U.S. government personnel files. “And content matters even less than the links you established—what does the Rolodex look like? If you establish that link chart, you go after who they are talking to.”

But that content also matters, and Trump has let secrets slip in the past, sharing intelligence with top Russian officials in the Oval Office that came to U.S. intelligence via Israel.

“What I worry about with officials talking on unclassified lines is that they think they can talk around classified information,” said Suzanne Spaulding, former Homeland Security undersecretary for cybersecurity under Obama. “I wouldn’t be surprised if Mr. Trump thinks he is being careful and talking around it in some coded way, but the sophisticated intelligence agency listening is going to be able to read between the lines,” said the cyber policy expert who is now the senior adviser for homeland security at the Center for Strategic and International Studies.

The White House and the Embassy of China in Washington, D.C., did not immediately respond to requests for comment.