US President Donald Trump says his wife Melania Trump thought he had a heart attack after she saw media reports of him visiting Walter Reed Medical Centre.

Speaking to reporters after his Tuesday cabinet meeting, POTUS said that the first lady was completely caught off-guard by his unscheduled visit to the medical centre for a routine checkup on Saturday. Melania Trump wondered if her husband had a heart attack.

"I went for a physical, and I came back. My wife said, 'Darling, are you Ok? What's wrong? Oh, they're reporting that you may have had a heart attack.' I said, 'Why did I have a heart attack.' 'Because you went to Walter Reed Medical Center,' that's where we go when we get the physicals," Trump said at the press conference.

"I was greeted with the news that I had a heart attack, I was greeted by our people in PR that I had a heart attack...these people are sick," he said about the media.

Adding that the American press is "dangerous", POTUS said: "We don't have freedom of speech in this country, we have the opposite. We have a very corrupt media, and I hope they can get their act together."

On Saturday, the US President paid a mysterious, unplanned visit to Walter Reed hospital, a military hospital in Bethesda, Maryland. His visit was followed by media speculations that the 73-year-old had "chest discomfort", reports Express.

Donald and Melania Trump
US President Donald Trump and First Lady Melania Trump walk to Marine One upon prior to departure from the South Lawn of the White House in Washington, DC, February 5, 2018 SAUL LOEB/AFP/Getty Images

However, Trump put a stop on the speculations after he tweeted on Saturday that his visit was for his yearly medical. "Began phase one of my yearly physical. Everything very good (great!). Will complete next year," he wrote.

Visited a great family of a young man under major surgery at the amazing Walter Reed Medical Center. Those are truly some of the best doctors anywhere in the world. Also began phase one of my yearly physical. Everything very good (great!). Will complete next year.

— Donald J. Trump (@realDonaldTrump) November 17, 2019

White House press secretary Stephanie Grisham also clarified on the day of the president's visit to the centre and told Fox News that Trump "decided to go to Walter Reed to kind of get a head start with some routine checkups as a part of his annual exam" as he had "a really busy year ahead."

The president's personal physician at the White House, US Navy Cmdr. Sean Conley, said the visit was a "routine, planned interim checkup" and was "kept off the record" due to scheduling uncertainties.