At least one Senate Republican senator has told reporters that he will not seek reelection in 2020 after a Washington Post report revealed allegations of sexual harassment against him and other Republicans.

In a letter sent Tuesday to Republican Sens.

Joe Manchin of West Virginia and Roy Blunt of Missouri, Sens.

Tom Cotton of Arkansas and John McCain of Arizona said that while they were unaware of the allegations against Manchin, Blunt and Cotton, they “do not consider it in the best interest of the Senate to continue serving.”

In a statement to the Post, Manchin said he has “no doubt” that the allegations are true and would be willing to return to the Senate, where he was first elected in 2015.

Blunt also said in a statement that he has heard nothing since the Post story was published Tuesday and will not be seeking reelection in 2018.

McCain, who has said that he “couldn’t imagine” retiring, is facing a primary challenge from incumbent Sen. Shelley Moore Capito. 

The Washington Post first reported Tuesday that Manchin had called Blunt’s campaign to tell him about the allegations.

The report also said that McCain had said he had heard nothing about the claims from his own office. 

Cotton, who is seeking his third term, also said he was unaware of any allegations against him, according to the Washington Post.

“I have been deeply offended by the inappropriate behavior of my colleagues in the Senate,” Cotton said.

“I have learned from my mistakes and I will not repeat them.”

Cotton said he plans to step down after the midterm elections next year.

“Senator Cotton is confident that the full facts will be made public, and I intend to do the same,” the senator said. 

Meanwhile, McCain’s spokesman said Tuesday that McCain “did not intend to comment” on the report. 

“Senator McCain will continue to focus on his role in the United States Senate, and will remain focused on advancing the interests of the American people,” McCain spokesman Scott McClellan said.