WASHINGTON, United States (AFP) — President Donald Trump on Friday tried to shut down reports that he is on the verge of sacking or forcing out his chief diplomat, Secretary of State Rex Tillerson.

Trump took to Twitter to brand reports of Tillerson’s imminent replacement “FAKE NEWS!”— although the US leader’s admission that he has had to overrule his top diplomat on policy will only fuel the rumours.

Tillerson is due to embark on a major European trip on Monday, despite anonymous White House leaks suggesting that he is to be replaced, perhaps within weeks, by a Trump loyalist.

“He’s not leaving and while we disagree on certain subjects, (I call the final shots), we work well together and America is highly respected again!” Trump declared.

The relationship between Trump and Tillerson has been dogged for months by reports of a rift. On Thursday, these came to a head when several US media outlets — citing White House sources — predicted Tillerson’s resignation and replacement by CIA chief Mike Pompeo.

Asked by reporters at a State Department photo call whether leaks from the White House were designed to force him out, Tillerson said: “It’s laughable. It’s laughable.”

The White House at first did little to downplay the reports, while a State Department spokeswoman insisted Tillerson’s position was safe, and the story drifted into a second day.

But later on Friday, Tillerson met Trump at the White House for a lunch with Defense Secretary Jim Mattis — an ally of Tillerson’s in Washington’s bureaucratic wars.

Next week, Tillerson is due to be in Europe to attend ministerial meetings of NATO in Brussels and the Organization of Security and Cooperation in Europe in Vienna.

There, he will also hold a bilateral US-Russia meeting with Foreign Minister Sergei Lavrov, in the latest long-shot bid to hammer out differences over the crises in Ukraine and Syria.