“President Barack Obama was born in the United States. Period,” said Trump. “Now we all want to get back to making America strong and great again,” he said at an event at a new Trump International Hotel down the street from the White House.

The New York businessman had brought up the birther controversy as far back as 2011 to make a mark in American politics in a way that would eventually prompt him to run for office this year.

During his presidential campaign he has readily trafficked in other theories that are the stuff of American supermarket tabloids, such as declaring that the father of Republican former rival Ted Cruz might have been linked to the assassin of the late President John F. Kennedy.

In making his announcement, Trump advanced a widely debunked claim that Clinton and her 2008 campaign had been the original birthers.

“Hillary Clinton and her campaign of 2008 started the birther controversy. I finished it. You know what I mean,” he said.

His campaign directed reporters to a 2007 memo from then-Clinton adviser Mark Penn, who had encouraged the Clinton campaign to go negative against Obama by saying that his Hawaiian birth and boyhood in Indonesia gave him limited roots in American values and culture.

Penn eventually left the Clinton campaign and his advice was never acted upon.

The Democratic National Committee condemned Trump’s bid to link Clinton to the birther idea. “He had the audacity to spout a new lie about the birther movement that he helped to build,” it said.

Clinton on Friday demanded Trump apologise to the president for having helped spread the birther idea and said Trump had tried to “delegitimize our first black president.”

“His campaign was founded on this outrageous lie. There is no erasing it in history,” Clinton said in an address to the Black Women’s Association in Washington.

Obama, who produced his Hawaiian birth certificate in 2011 to prove doubters wrong, had famously mocked Trump over the birther issue at a White House Correspondents Association dinner as the wealthy businessman sat in the audience fuming.

Still Trump clung to the notion that Obama was foreign-born, saying in 2012 that the birth certificate was a fraud.

On Friday, Obama was asked for his reaction to the latest Trump declaration.

“I’m shocked that a question like that has come up at a time when we have so many other things to do. Well, I’m not that shocked actually. It’s fairly typical. We’ve got other things to attend to. I was pretty confident about where I was born,” he said.

The birther conspiracies, which aim to challenge the legality of Obama’s presidency, incense black Americans whose votes Trump has been trying to court.

Members of the Congressional Black Caucus held a news conference to urge African-American voters to resist any temptation to support Trump.

“I’m wondering when this country is going to awaken from this reality show,” said Representative Brenda Lawrence, a Democrat.

The issue has not been a factor in the campaign for this year’s presidential election, but it resurfaced in recent days, taking the focus of Trump’s campaign away from topics such as immigration, trade and the economy, which he has been using to hit Clinton.

Trump had revived the birther controversy on Thursday in an interview with The Washington Post when he declined to say whether he believed Obama was born in Hawaii. A US president must be a natural-born citizen.

Trump had promised “a big announcement” about the birther issue on Friday, giving the impression it was the purpose of the event at his hotel.

But, instead, he held off saying anything about it through more than 20 minutes of endorsements from military veterans. Only after that did Trump make a brief statement about Obama’s birth.

Trump, a real estate mogul, devoted more time at the beginning of the event to talking about his hotel where the event took place. He ignored reporters’ shouted questions.