A final decision confirming that King Charles and Queen Camilla's state visit will go ahead is expected later on Sunday, the BBC understands, after a shooting incident in Washington DC raised security concerns.
The UK government has to be satisfied, but all indications suggest the state visit will begin as planned on Monday, possibly with some minor adjustments to more public-facing events.
Donald Trump also seems to expect the trip to go ahead, telling Fox News: "King Charles is coming, and he's a great guy."
Buckingham Palace said the King was "greatly relieved" to hear that the US president, Melania Trump and other guests at the White House Correspondents' Dinner had been unharmed.
It's understood that the King and Queen privately reached out to the Trumps to express their sympathies for those caught up in the attack.
The couple and other senior administration figures were
evacuated from the dinner after a man fired several shots while attempting to enter the venue. The suspect, identified in US media as 31-year-old Cole Tomas Allen, was detained at the scene and was believed to have been targeting Trump administration officials.
There have already been talks about the security around the King and Queen's trip, concerning "to what degree the events of Saturday evening may or may not impact on the operational planning for the visit", the Palace said earlier.
Any last-minute changes to the planned itinerary are thought to be less likely to be at the set-piece occasions, which are in secure locations such as the White House and the US Congress.
Trump appeared confident on Sunday that the trip would still go ahead, telling Fox: "He's coming, and we're going to have a great time."
The US president added: "He's really a fantastic person and a tremendous representative."
Acting US Attorney General Todd Blanche said he was "very confident" the King and Queen will be safe during the four-day visit, telling NBC News that Saturday night's incident showed the US security system worked.
Senior government minister Darren Jones told the BBC earlier on Sunday that the King's state visit would have "appropriate security in place in relation to the risk".