President Trump on Thursday denied a report that he often calls friends to gripe or solicit advice on his unsecure iPhones, allowing Chinese spies to listen in and gain valuable insights into how to deal with the U.S. administration.

“The so-called experts on Trump over at the New York Times wrote a long and boring article on my cellphone usage that is so incorrect I do not have time here to correct it,” Trump said in a predawn tweet. “I only use Government Phones, and have only one seldom used government cell phone. Story is soooo wrong!”

The Times report, which prompted fresh calls from Democrats to investigate the president’s cellphone usage, said that Trump’s aides have repeatedly warned him that his mobile calls are not secure, and they have told him that Russian spies are also routinely eavesdropping on the calls. The Times said that American intelligence reports have indicated that Chinese spies are listening.

“The president’s use of his personal iPhone would raise concerns for intelligence officials because hostile or even non-hostile foreign intelligence services might be listening in on the conversations and learning who he’s talking to, who he’s influenced by and who might be a rich source of information,” said Mary McCord, a former senior Justice Department official now at Georgetown University Law Center.

The intelligence community has long been concerned that the president’s use of his personal iPhones potentially opens his communications to surveillance by foreign adversaries, including the Chinese and Russians, U.S. officials said.

“This was not a secret” early in the administration, said one former senior White House official, who spoke on the condition of anonymity to talk about a sensitive matter. “There were lots of people who were worried about this. I just assumed that anything he said was being listened to by a friend, a frenemy or all of the above.”

The issue is not what type of smartphone is used, but that any unsecured communication over a cellular network is vulnerable to surveillance by a foreign government.

In a second tweet on the subject later Thursday morning, Trump insisted his cellphone usage is rare. “I like Hard Lines,” he wrote. “Just more made up Fake News!”

The Times said that aides had pressured Trump into using his secure White House landline more often lately but that he has refused to give up his iPhones.

On Thursday night, White House spokesman Hogan Gidley said Trump has one “official” government iPhone.

“This phone security follows industry best practices and is closely managed under government supervision in conjunction with recommendations from industry partners,” Gidley said. “The phone is rotated on a regular basis and is constantly monitored for any security vulnerabilities and attacks, in accordance with recommendations from the intelligence community.”

A Chinese official also denied the Times report earlier Thursday, dismissing it as “fake news.”

During a briefing in Beijing, Hua Chunying, a Foreign Ministry spokeswoman, said that if there are security concerns, Trump could switch to a phone made by Huawei, a Chinese company, or cut off communications altogether.

“Seeing this report, I feel there are those in America who are working all-out to win the Oscar for best screenplay,” Hua said.

The Times issued a statement saying it “is confident in the accuracy of our reporting.”

Shortly after Trump’s tweet was sent Thursday, former aide Omarosa Manigault Newman, who was fired in December, took to Twitter to push back against his denial.

“Clearly #45 memory is fading fast,” Manigault Newman wrote, referring to the president. “He ALWAYS used his personal iPhone in WH for calls even after being told over and over again about the security risk. He disliked his secure gov issued cell- he said it was slow and ‘buggy.’ ”

The report on Trump’s phone use was met with alarm from Democratic lawmakers.

“This is a big problem, if true,” Sen. Mark R. Warner (D-Va.), vice chairman of the Senate Intelligence Committee, said Wednesday night on Twitter. “The intelligence community works hard to defend us against foreign espionage. The last thing we need is for the President to be jeopardizing national security through sheer carelessness.”

Rep. Don Beyer (D-Va.) reiterated his previous calls for an inquiry into Trump’s cellphone use.

“When Trump took office, I warned Republicans about the dangers of his cell phone usage,” he tweeted. “No oversight was conducted under their watch. . . . His selfishness is jeopardizing our national security.”