The U. N. Human Rights Committee and leading international human rights organizations have repeatedly urged the Central Asian nation's authorities to release Askarov, noting his deteriorating health.
Askarov, an ethnic Uzbek rights activist, has been sentenced to life in prison for his alleged role in the deadly ethnic violence in southern Kyrgyzstan in 2010.
Before his detention, Askarov had led a human rights organization in southern Kyrgyzstan focused on prison conditions and police treatment of detainees.
Human Rights Watch and other rights groups said Askarovs detention and trial were marred by serious human rights violations, including credible allegations of torture.
In 2016, the U.N. Human Rights Committee found that Askarov was arbitrarily detained, held in inhumane conditions, tortured and mistreated.