Seeking to draw under a line under the controversy as more images and videos of him wearing blackface emerged in the media, the leader of the Liberal Party declined to answer questions from reporters as to how many instances there may have been.

He also said he had never told anyone about the incidents, including officials who vetted him before he joined the party and became a member of parliament.

“I never talked about this,” he said at a press conference in Winnipeg, Manitoba. “Quite frankly, I was embarrassed.”

He added: “It is something that people who live with the kind of discrimination that far too many people do, because of the colour of their skin or their history or their origins or their language or their religion, face on a regular basis, and I didn’t see that from the layers of privilege that I have. And for that I am deeply sorry, and I apologise.”

Justin Trudeau Show all 8 1 /8 Justin Trudeau Justin Trudeau Day out The family get in the boat with climate change AP Justin Trudeau Keeping fit Jogging over the Alexandria bridge with the Mexican president AP Justin Trudeau Family comes first “Sophie inspires me every day to be better. I wouldn’t be here tonight if it weren’t for her leadership and her example." AP Justin Trudeau Three-way handshake Trudeau has vowed to strengthen international relations. Twitter Justin Trudeau Bromance Friendship with the White House The White House Justin Trudeau Pandas Just because. Twitter Justin Trudeau Yoga The plank became an internet sensation Twitter Justin Trudeau Making history Trudeau's gender-balanced cabinet was the first of its kind AP

Mr Trudeau, 47, eldest son of the late prime minister Pierre Trudeau, and who was first elected premier in 2015, has been on the back foot since the first images emerged this week. They showed him with his face in dark make-up at a party at a school where he was teaching in 2001, aged 29.

The school yearbook picture, obtained by Time magazine, show him wearing a turban for an Arabian Nights-themed fancy dress party at the West Point Grey Academy in Vancouver.

The prime minister, who launched his re-election campaign just a week ago, said he should have known better. “I’m pissed off at myself, I’m disappointed in myself,” Mr Trudeau told reporters.

But on Thursday, the problem appeared to get worse for Mr Trudeau, as other images of him in blackface emerged. Asked how many incidents there may have been, he replied: “I’m wary of being definitive about this because the recent pictures that came out I had not remembered.”

He said he had already shared “the moments I recollected”, adding: “But I recognise that it is something absolutely unacceptable to do. And I appreciate calling it makeup, but it was blackface, and that is just not right.”

Unearthed Justin Trudeau video shows him in blackface

The scandal is similar to others that have caught out politicians elsewhere. Earlier this year, Virginia governor Ralph Northam faced repeated calls to stand down after a racist picture surfaced from his 1984 medical school yearbook. He did not do so.

The episode is deeply embarrassing for Mr Trudeau and disappointing for his supporters. Despite his privileged background, he has long pitched himself as champion of the marginalised, and has promoted a number of women and ethnic minorities to his cabinet.

To his admirers in the US, he has been the opposite of Donald Trump.

Polls show Mr Trudeau’s Liberal Party being pressed hard ahead of election day on 21 October. Conservative leader Andrew Scheer has said Mr Trudeau was “not fit to govern this country”.

Asked on Thursday if he intended to stand aside as leader of the party, Mr Trudeau said he had spent much of the day speaking to colleagues and community leaders.

“I will continue to do the work that is necessary to keep us moving forward in the right way,” he said. “Canadians have an important choice to make on October 21 and I trust Canadians to make that right choice.”

Greg Fergus, a Liberal member of parliament who is black, said there was a lot of confusion and hurt in the black community but noted that the prime minister had apologised.

He pointed out that it was Mr Trudeau who put Viola Desmond, a black woman who refused to leave the whites-only section of a Canadian movie theatre in 1944, on Canada’s $10 bill.

Mr Fergus added: “I think the real measure of the man, and I think the thing we need to be talking about, is all the amazing things we have done for diversity.”

Mitzie Hunter, a Liberal who is running to lead the party in Ontario provincial politics and is black, tweeted: “I know it is not representative of the man he is. This is a teachable moment for all of us. I accept his apology and I hope Canadians do too.”