Former Mossad chief Meir Dagan was in serious but stable condition Wednesday night after receiving a liver transplant in a Belarusian hospital.

Earlier Wednesday, a hospital official had said Dagan’s temperature was rising and that he was being treated in the intensive care unit. But Dagan’s condition improved gradually during the day and stabilized, hospital sources and friends of Dagan said.

Dagan, 67, successfully underwent the liver transplant last week, but complications resulting from the surgery began thereafter.

The ex-spy chief was anesthetized and hooked up to a ventilator, according to a friend who accompanied Dagan to Belarus.

News of Dagan’s transplant broke on Tuesday after Belarusian President Alexander Lukashenko said he was being treated in Minsk.

Dagan’s associates reportedly fear his safety was compromised by Lukashenko’s announcement, and that Dagan could now be targeted by Hezbollah, Syria, or Iran. They added that Israel may demand increased security on the hospital.

The transplant was performed by Dr. Daniel Azoulay of the Paris transplant center; senior Israeli doctors assisted.

American and German doctors were asked to perform the operation, but “no one wanted to carry out a liver transplant operation on a former head of the Mossad,” Lukashenko said.

Channel 2 reported that Dagan had been set to undergo the surgery in India, but that the Indian authorities ultimately refused to treat him because of his Mossad past.

Prime Minister Benjamin Netanyahu and other Israeli officials reportedly intervened to try to help Dagan find a donor and an appropriate hospital for the surgery.

Prof. Yaakov Lavie, of the transplant center at Tel Aviv’s Tel Hashomer Hospital, said that Israeli health regulations set 65 as the maximum age for a liver transplant.

Dagan completed his service as head of the Israeli spy agency in 2010, and has since been a leading public critic of what he called the “stupid” idea of Israel striking Iran’s nuclear facilities, considering such action at this stage as dangerously premature.