Former President Donald J. Trump said Saturday that the impeachment proceedings against Ken Paxton, the Texas attorney general, were unfair and vowed to fight lawmakers who sought impeachment.

Trump said in a statement on Truth Social, his social media platform, that moving to impeach Paxton was contrary to the will of the voters who elected Paxton to a third term by a wide margin in November.

“Hopefully the Republicans in the Texas House of Representatives agree that this is a very unfair process that should not be allowed to happen or continue,” Trump said. wrote. “I’ll fight you if he does.”

A Republican-led House panel accused Mr. Paxton, also a Republican, of unethical behavior, including accepting favors from a real estate investor in exchange for access and assistance from his office.

Trump was far from the only conservative figure to pledge support for Paxton in response to the allegations.

Stephen Miller, an adviser to former President Donald J. Trump, urged his supporters to “Support Ken.”

Trump’s eldest son, Donald Trump Jr., called the impeachment efforts by the Texas House of Representatives a “witch hunt” and a “disgrace.”

And Kyle Rittenhouse, the 20-year-old who has become a conservative star since he was acquitted of all charges in the shooting of three men during protests in response to a police shooting in Kenosha, Wisconsin, praised Paxton for being a “pro-gun” attorney general.

Mr. Paxton has also been posting on social media, promoting an interview he gave to Rep. Matt Gaetz, a Florida Republican, and issuing a statement criticizing the investigation into his conduct. He said lawmakers had requested false testimony “with the aim of manipulating and misleading the public.”

In addition to conservative political figures, Paxton was also praised online by musician Ted Nugent, who is an outspoken conservative and Trump supporter.

“The Nugent family and all Texas Constitutionalists support the great Attorney General Ken Paxton,” Nugent wrote on Twitter.