Canadian Prime Minister Mark Carney has said Canadians were not "impressed" by the UK government's invitation to US President Donald Trump for a second state visit.

The newly elected Carney told Sky News that the UK's invitation earlier this year did not help Canadians, who were facing repeated comments from Trump about making Canada the 51st US state.

"To be frank, [Canadians] weren't impressed by that gesture... given the circumstance," he said. "It was at a time when we were being quite clear about the issues around sovereignty."

Prime Minister Sir Keir Starmer invited Trump to come to the UK for a visit during a meeting at the White House in February.

Asked whether the invitation was "appropriate", Carney said that was a decision for the government of the UK and Buckingham Palace.

"I leave the diplomacy to the UK government," he said.

The BBC has contacted the Carney's office and No 10 for comment.

When reached by the BBC, Buckingham Palace said the issue was a matter for the Foreign and Commonwealth Office and did not comment further.

The criticism from Carney comes as the Canadians prepare to welcome King Charles III and Queen Camilla at the end of this month for a royal visit.

During the Sky News interview, Carney said his invitation for the King - Canada's head of state - to attend the opening of Canada's Parliament "is not coincidental".

"It is also a reaffirming moment, will be a reaffirming," Carney said, saying issues around Canada's sovereignty "have been accentuated by the president".

During his visit, the King will also read the Speech from the Throne - a function usually carried out by the governor general.

The last time this happened was in October 1977 when Queen Elizabeth II read the speech for the second time in Canada's history. The first was in 1957.

Since returning to the White House, Trump has made repeated comments undermining Canada's sovereignty, including that the Canadian border is an "artificially drawn line".

Meanwhile, Carney has firmly said Canada is "not for sale, ever".

Carney - who said he would only meet the US president "until we get the respect we deserve" - sat down with Trump in Washington DC last week to begin negotiations on a new trade and security relationship.

During the visit, Trump repeated his 51st state comments.

Pressed on that, Carney told Sky News that Trump has shifted his tone from "expectation to a desire for that to happen".

"He also came from a place where he recognised that was not going to happen."