Mike Pence. (Kyodo)

Former U.S. Vice President Mike Pence on Monday filed paperwork to join an increasingly crowded field of Republican candidates vying for the party's 2024 presidential nomination.

His entrance into the race pits him against former President Donald Trump, the current front-runner, whom he served in the White House for four years through 2021.

Since leaving office, however, the 63-year-old Pence has distanced himself from Trump, making his most scathing comments in March about the former president's role in the attack on the U.S. Capitol in January 2021.

He said Trump's encouragement of rioters and his reckless words leading up to the attack "endangered my family and everyone at the Capitol that day," and that history will hold the 76-year-old former president "accountable."

Pence, known as a staunch conservative, served as a House of Representatives member for more than 10 years before becoming the governor of Indiana in 2013.

He is scheduled to launch his presidential campaign on Wednesday, according to major U.S. media, with the date coinciding with his 64th birthday.

Among Republicans challenging Trump for the 2024 nomination, opinion polls have shown that only Florida Gov. Ron DeSantis, 44, has managed to reach double-digit support so far.