Donald Trump

Mr Trump and his wife Melania were greeted in the Saudi capital by King Salman on Saturday morning local time.

The eight-day trip will also take in Israel, the Palestinian territories, Brussels, the Vatican, and Sicily.

The visit comes as Mr Trump faces uproar at home following his sacking of FBI director James Comey.

This is in an effort to prepare for what officials still believe is a distant possibility that President Donald Trump could have to fend off attempts to remove him from office, two people briefed on the discussions tell CNN.

White House officials believe the President has the backing of Republican allies in Congress and that impeachment is not in the cards, according to the people briefed on the legal discussions. Even Democrats have tried to calm impeachment talk out of concern it is premature.

Citing a document summarising the meeting in the Oval Office last week, the New York Times said Mr Trump called Mr Comey a "real nut job".

Mr Comey had been running an inquiry into possible collusion between Russia and Donald Trump's election campaign.

The White House has not disputed the language used.

The report was published just as Mr Trump took off on a flight to the Middle East for the first leg of his first foreign tour as president.

And, according to a new report, he has gone even further than that in private, telling then-FBI Director James Comey that Comey should consider locking reporters up.

Trump said this to Comey during a meeting in the Oval Office in February, according to a New York Times report Tuesday. The request came during the same meeting in which Trump is said to have asked Comey to drop the federal investigation into former national security adviser Michael Flynn, potentially interfering with the investigation into alleged ties between Trump's presidential campaign and Russian officials.

The diplomat described the Western Wall in Jerusalem's Old City -- one of Judaism's holiest sites -- as being in the West Bank.

The Israeli Prime Minister's office said it was shocked by the comments and said it had asked the United States to explain what was meant by them.

According to Israel's Channel 2 News, a member of the US delegation preparing for Trump's visit made the comment about the wall when Israeli officials suggested a photographer shoot video of the President during a proposed visit to the site.

"As President I wanted to share with Russia (at an openly scheduled W.H. meeting) which I have the absolute right to do, facts pertaining to terrorism and airline flight safety, Humanitarian reasons, plus I want Russia to greatly step up their fight against ISIS & terrorism," he tweeted.

Two former officials knowledgeable of the situation confirmed to CNN that the main points of the Post story are accurate: The President shared classified information with the Russian foreign minister.

The President did not directly reveal the source of the information, but intelligence officials told CNN that there is concern that Russia will be able to figure out the highly sensitive source.

Senate Democratic leader Charles Schumer warned that destroying any tapes would break the law.

Republican Senator Lindsey Graham said the White House needed to "clear the air" about whether tapes existed.

The comments come after Mr Trump tweeted what appeared to be a thinly veiled threat to the former FBI chief.

He warned Mr Comey last week against talking to the media, saying he had "better hope there are no tapes" of their conversations.

The White House has neither confirmed nor denied the presence of any tapes.

Mr Trump's main advisers are due to meet on Tuesday to review his threat to quit the 2015 Paris Agreement to limit global warming, which is backed by governments as diverse as China, OPEC oil producers and the poorest African states.

At UN negotiations that began on Monday in the German city of Bonn, the chairman of the talks, Moroccan Foreign Minister Salaheddine Mezouar, said global momentum to combat climate change was irreversible and it would be "difficult or foolish" for anyone to defy public pressure for action.

These latest talks are aimed at developing the rules for implementing the accord signed in the French capital in 2015.

But there is a growing worry that President Trump might soon pull out of the historic deal.

Some delegates say such a move would be a body blow for the landmark deal.