JERUSALEM — Prime Minister Ariel Sharon had surgery overnight to replace his breathing tube, the hospital where he is being treated said in a statement Wednesday.

Sharon, who has been in a coma since suffering a stroke Jan. 4, remains in critical but stable condition, the statement from Jerusalem’s Hadassah Hospital said.

“The breathing tube was changed overnight due to a technical problem. The successful procedure was conducted in the operating room. The prime minister was taken back to his room in the morning,” the statement said.

The 77-year-old Israeli leader underwent a tracheotomy Sunday to help him breathe. He has been taken off sedatives.