WASHINGTON (Reuters) – Republican Donald Trump said he planned to address President Barack Obama’s citizenship on Friday, prompting a call from Democratic rival Hillary Clinton to apologize for reviving the so-called birther movement which questions whether Obama was born in the United States.

“I’m going to have a big announcement on it today,” Trump said in an interview with Fox Business Network, a day after he refused in a newspaper interview to say whether he believed Obama was born in the United States.

Trump was due to discuss the issue in a speech at a new hotel his company is opening in Washington.

The New York businessman several years ago led the birther movement aimed at Obama, who was born in Hawaii to an American mother and a Kenyan father.

The issue has not been a major factor in the campaign for the Nov. 8 presidential election and by bringing it up again Trump takes the focus of his campaign away from topics such as immigration, trade and the economy, which he has been using to hit Clinton.

Trump has recovered ground against Clinton in recent national opinion polls after revamping his campaign staff in August and taking steps to give a more polished performance on the campaign trail.

But the birther movement, which casts doubt over whether Obama is legally able to be president, incenses black Americans whose votes Trump has been trying to court.

“Barack Obama was born in America, plain and simple, and Donald Trump owes him and the American people an apology,” Clinton said in an address to the Black Women’s Association in Washington. She said Trump was trying “to delegitimize our first black president.”

A few years into his presidency, Obama, the first African American to win the White House, released a longer version of his birth certificate to answer those who suggested he was not U.S. born.

Trump on Thursday declined to say whether he believed Obama was born in Hawaii during an interview with The Washington Post.

“I’ll answer that question at the right time. I just don’t want to answer it yet,” Trump told the newspaper.

His campaign released a statement later in the day saying the candidate is convinced of the legitimacy of Obama’s presidency. A U.S. president must be a natural-born citizen.

“In 2011, Mr. Trump was finally able to bring this ugly incident to its conclusion by successfully compelling President Obama to release his birth certificate,” Trump spokesman Jason Miller said in the statement.

“Having successfully obtained President Obama’s birth certificate when others could not, Mr. Trump believes that President Obama was born in the United States,” he said.

(Reporting by Doina Chiacu and Susan Heavey; Editing by Alistair Bell)

Photo: Republican presidential nominee Donald Trump speaks to the Economic Club of New York luncheon in Manhattan, New York, U.S., September 15, 2016.  REUTERS/Mike Segar