US President Joe Biden will be the first sitting president to deliver a Sunday sermon at Martin Luther King Jr.'s church in Atlanta, as he marks a national holiday celebrating the civil rights leader, White House officials said on Friday.

Biden will speak at Ebenezer Baptist Church on Sunday at the invitation of the church's pastor, Democratic Senator Raphael Warnock, on what would have been King's 94th birthday. King was killed at age 39 in 1968 by an avowed segregationist.

"This is an inflection point in history and the president will deliver remarks reflecting Dr. King's life and legacy and they that way we can go forward together," Keisha Lance Bottoms, former Atlanta mayor and director of the White House Office of Public Engagement, told reporters.

He will speak on a number of issues "including how important it is that we have access to our democracy," she said.

On Monday, Jan. 16, a national holiday to celebrate King, Biden will meet with civil rights advocate Al Sharpton in Washington, and speak to his group, the National Action Network.

Biden was elected in 2020 with strong support from Black voters, after pledging to do more to expand voting rights and address other racial justice issues. But some activist groups boycotted his 2022 speech honoring King, disappointed by his lack of action.

"The president has done and will continue to do all that he can do in his executive powers," Lance Bottoms said. "Now we need Congress to act."

"Ebenezer is a cornerstone of the Black community and I'm sure the president will get an earful on what our needs and our desires are for our country."