WASHINGTON (AFP) - Former Republican governor Mark Sanford announced on Sunday (Sept 8) he is entering the race for his party's presidential nomination, in a long-shot challenge to President Donald Trump.

Sanford, who would be the third Republican to mount a primary bid against Trump, said he had decided to run because of the "astounding" debt and deficits piled up during his presidency.

"I think as a Republican party we have lost our way," he said in an interview with Fox News Sunday.

"The president has called himself the king of debt, has a familiarity and comfort level with debt that I think ultimately is leading us in the wrong direction."

Sanford's decision comes amid reports that Republican officials in some states, including his home state of South Carolina as well as Nevada and Arizona, are considering cancelling their 2020 primaries.

Asked whether he really thought he could defeat Trump, Sanford replied: "I'm saying, you never know."

"I'm listing my goals, my primary goals to say let's go out and force, or try and create a conversation on that which is not being talked about in this presidential cycle," he said.

"The thing that has been lacking in this debate has been an earnest and real conversation on debt and deficits in government spending."

Sanford was governor of South Carolina from 2003 to 2011, and served two separate stints in the House of Representatives, but lost a party primary in 2018.

Also running against Trump for the Republican nomination are Joe Walsh, a former Tea Party firebrand who served a single term in Congress, and William Weld, a former Massachusetts governor.