US Senator Tim Scott is running to become the first Black Republican president, papers filed with the Federal Election Commission showed on Friday.

The 57-year-old, who had been widely expected to jump into the race since launching a presidential exploratory committee in April, is planning to hold his official launch in his home town of North Charleston, South Carolina, on Monday.

He has spent recent months visiting the states considered crucial to gaining early momentum in the Republican nominating contest, where he has underlined his Christian faith and the conservative values he learned growing up in a poor, single-parent household.

He has also played up his unique perspective as the only African American on the Republican side of the US Senate.

"American families are starving for hope. We need to have faith. Faith in God, faith in each other, and faith in America," he tweeted on Thursday.

Scott joins a burgeoning field hoping to reel in frontrunner Donald Trump, but he faces a daunting task with recent polling showing his support at around two percent – an average of 54 points behind the former president.

Other candidates include Trump's first United Nations ambassador Nikki Haley, the former South Carolina governor, as well as ex-Arkansas governor Asa Hutchinson, tech entrepreneur Vivek Ramaswamy and talk radio host Larry Elder, the first African American to enter the race.

Trump's closest rival is Florida Governor Ron DeSantis, who is expected to launch his own presidential bid next week.

Scott, who is considered one of the Senate's most formidable fundraisers, said last month he had $22 million in his Senate campaign account and launched a $6 million ad buy in Iowa and New Hampshire. (AFP)