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".

Shadow home secretary Chris Philp, meanwhile, said that it was "vital" the King was properly protected, and urged US and UK teams to review the monarch's security overnight.

One Secret Service agent was shot during the incident on Saturday night but was saved by his bullet-proof vest, the president said. No other injures were reported.

Even before last night's incident, security for the King and Queen's state visit was going to be very tight. Now it will be going up another level.

Potential adaptations to the royal visit - the first to the US since Elizabeth II's in 2007 - could include reconsidering the King's interactions with the public, as he usually likes to meet crowds on such trips.

When Trump visited the UK last autumn, almost all the events happened inside Windsor Castle. He was carried by helicopter in and out of that secure bubble, and so was kept away from any contact with the public.

The King is expected to address both houses of Congress, visit the 9/11 memorial in New York and attend a wreath laying to honour fallen US and UK soldiers in Virginia.

The state visit has already proven diplomatically challenging for those planning it.

It is due to take place days after reports emerged that the US could review its position on UK sovereignty over the Falklands Islands.

Trump has also been highly critical of the UK government and other allies over their response to the Iran war.

But despite these political differences, the US president has been steadfast in his admiration for the monarchy and the King, telling the BBC earlier this week that the state visit could help repair relations between the US and UK.

"I know him well, I've known him for years," the president said. "He's a brave man, and he's a great man."

Sir Keir Starmer offered his "best wishes" to Trump and Melania following the "shocking scenes" that unfolded on Saturday night.

The UK prime minister expressed his relief that the president and first lady were safe in a phone call on Sunday, and wished a speedy recovery to the injured officer.

Liberal Democrat leader Sir Ed Davey likewise condemned the "really shocking scenes", writing on X: "Political violence is wrong. We must all condemn this attack and be thankful no lives were lost."

Reform UK leader Nigel Farage said it was a relief that all attendees were safe, adding: "However much we disagree about politics, if violence is used we all lose."