WASHINGTON (Reuters) - Democrat John Conyers, the longest serving member of the U.S. House of Representatives, stepped down on Tuesday after multiple accusations of sexual misconduct, the first member of Congress to leave his seat during a wave of high-profile harassment allegations.

Conyers, a leading figure in civil rights and Democratic politics who represented the Detroit area for over half a century, endorsed his son to take his place.

“I am in the process of putting my retirement plans together and will have more on that very soon ... I am retiring today,” Conyers, 88, said in a radio interview from a hospital where he is being treated for stress-related illness.

“I have a great family here and especially in my oldest boy, John Conyers III, who incidentally I endorse to replace me in my seat in Congress,” Conyers said.

His resignation letter was later read in the House chamber, making his departure official. Michigan’s Republican governor, Rick Snyder, said he would review dates for a special election.

Conyers’ great-nephew has also announced he would run.

The growing number of accusations against Conyers, a founder of the Congressional Black Caucus who hired Rosa Parks as an aide after winning his first term in 1964, troubled party leaders.

U.S. Representative John Conyers (D-MI) participates in a House Judiciary Committee hearing on Capitol Hill in Washington, U.S. July 12, 2016. REUTERS/Jonathan Ernst

House Democratic Leader Nancy Pelosi was criticized for calling Conyers an “icon” before calling for his resignation.

But others said the issue was clear, if difficult.

“We have to recognize and be able to hold the dueling possibilities that somebody can be a great man and have done great things for our country and for civil rights, but also have done terrible things that require accountability,” said Representative Pramila Jayapal.

The House Ethics Committee opened an investigation last week.

Conyers repeated his denial of harassment allegations in the radio interview. “They are not accurate or they are not true.”

Congress has been grappling with harassment policy amid a string of cases involving prominent men, including Republican President Donald Trump, Democratic Senator Al Franken and Republican Senate candidate Roy Moore.

Trump and Moore have denied wrongdoing. Franken apologized.

Conyers, who had risen to be chairman of the powerful House Judiciary Committee, stepped down last month as the panel’s senior Democrat.

Several former women aides have accused him of misdeeds such as inappropriate touching and showing up for a meeting in only his underwear.

But others issued a statement defending him, saying they did not see him behave inappropriately.