A UN court on Tuesday denied a request for early release from Ratko Mladic, a military leader during the 1990s Yugoslav wars known as the "Butcher of Bosnia".
Mladic, sentenced to life imprisonment in 2017 over genocide and war crimes, filed a request to be freed on June 3 saying he only had a few months to live.
But a judge at the International Residual Mechanism for Criminal Tribunals, the court tasked with handling remaining cases from the Yugoslav war crimes tribunal, said his condition did not meet the threshold of an "acute terminal illness" required for release.
"I acknowledge that Mladic's current condition, which requires dependency on others for activities of daily living, is precarious," judge Graciela Gatti Santana said in a 12-page decision issued in The Hague.
"Nonetheless, Mladic continues to receive very comprehensive and compassionate care, as amply supported by medical reports.
"The information before me demonstrates that the compelling humanitarian circumstances invoked by Mladic as a basis for his release are not substantiated."
Mladic, now in his 80s, was sentenced by the UN tribunal for the former Yugoslavia for his role in the siege of Sarajevo and the 1995 Srebrenica massacre.
Some 8,000 Muslim men and boys were killed in Srebrenica by Bosnian Serb forces in July that year.
Mladic has long been described by his lawyers as sick and frail and in their latest request they said he suffered from an incurable illness and that "his remaining life expectancy is measured in months", according to a filing seen by AFP.
His defence first sought provisional release on medical grounds in 2017.
Santana said Mladic's continued incarceration was neither "inhuman nor degrading".
Mladic was arrested in Serbia in 2011 after 16 years on the run and is serving his sentence in The Hague.
His son, Darko, often speaks to Serbian media about the poor health of his father, who is still seen as a hero by some in Serbia.