Washington - Ben Carson, who became a conservative political star after a career as a neurosurgeon that included directing the first surgery to separate twins connected at the back of the head, planned to formally announce on Monday that he will seek the Republican presidential nomination in 2016.
Carson, who has never run for public office and will be a longshot candidate, is expected to be the only high-profile African-American to enter the Republican presidential primary as he tries to parlay his success as an author and speaker into a competitive campaign against established politicians.
"I'm willing to be part of the equation and therefore, I'm announcing my candidacy for president of the United States of America," he said in an interview aired Sunday night by Ohio's WKRC television station.
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He is set to make a more formal announcement during a speech from his native Detroit on Monday.
Carson joins a crowded Republican primary field that could feature as many as two dozen candidates. Three other Republican senators have already entered the race: Marco Rubio of Florida, Ted Cruz of Texas and Rand Paul of Kentucky.
Lack of political experience
Former Florida Gov. Jeb Bush is also considered a leading candidate though he has not formally announced. Former first lady, US senator and secretary of state Hillary Rodham Clinton appears unlikely to face a formidable Democratic opponent in that party's primary campaign.
Carson earned national acclaim during 29 years leading the pediatric neurosurgery unit of Johns Hopkins Children's Centre in Baltimore, where he still lives. He directed the first surgery to separate twins connected at the back of the head. His career was notable enough to inspire the 2009 movie, "Gifted Hands," with actor Cuba Gooding Jr. depicting Carson.
He told the Associated Press in an interview earlier this year that his lack of political experience is an asset.
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"I see myself as a logical American who has common sense," he continued, "and I think that's going to resonate with a lot of American, regardless of their political party."
The 63-year-old Detroit native remains largely unknown outside of conservative activists who have embraced him since his address at the 2013 National Prayer Breakfast, where he offered a withering critique of the modern welfare state and the nation's overall direction.
The speech restated themes from Carson's 2012 book "America the Beautiful", but he excited conservatives by doing so with President Barack Obama sitting just feet away.
Carson has since become a forceful critic of the nation's first black president on everything from health care to foreign policy. Carson also offers himself as a counter to other notable African-American commentators with more liberal views.
Most recently, Carson has spoken out on the unrest in his hometown, where residents have protested and rioted in the wake of Freddie Gray dying while in custody of the Baltimore Police Department. In a Time magazine opinion article, Carson decried the protests and related vandalism as "gross misconduct".
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Carson moved to Palm Beach, Florida, after his retirement from Johns Hopkins, but he is announcing his campaign in his hometown of Detroit, where his mother raised him and his brother in poverty.
He attributes his politics to his upbringing, often describing his neighbourhood culture as one where residents celebrated any new announcement of government support. Still, he acknowledges that his mother received welfare aid, and he insists that he supports "a safety net for the people who need a safety net".
Carson is a staunch social conservative, opposing abortion rights and same-sex marriage, views he attributes to his personal faith as a practicing Christian.