Two courts in the Russian city of Vladimir have postponed hearings into complaints filed by imprisoned opposition politician Aleksei Navalny "until his whereabouts are ascertained."
Navalny spokeswoman Kira Yarmysh wrote on X that courts had scheduled seven hearings into Navalny's complaints on December 18. It was unclear if the others would be canceled as well.
Hearings into Navalny's claims were postponed on December 15 as well, pending information about his whereabouts.
Navalny's associates reported on December 18 that their leader has not been heard from for 13 days.
It is his longest absence since he was taken into captivity in January 2021 after returning to Russia from Germany, where he underwent treatment for a near-fatal nerve-agent poisoning that he believes was carried out by Russian security operatives at the behest of authoritarian President Vladimir Putin.
Council of Europe Secretary-General Marija Pejcinovic Buric wrote on X that she had "serious concerns" about Navlalny and called for his release "in line with relevant judgements of the European Court of Human Rights."
SEE ALSO: The Week In Russia: 'An Enforced Disappearance'Navalny’s supporters have launched an Internet campaign using the hashtag #WhereIsNavalny.
Prison officials have said he is no longer in the Vladimir region prison where he had been serving a 19-year term but have refused to say where he is. In a statement on December 12, the Federal Penitentiary Service (FSIN) said only that Navalny had left "for a penal institution outside the borders of Vladimir Oblast."
The process of transferring convicts in Russia, known as "etap," involves "vagonzaks" -- trains specifically designed for prisoners.
Such trains have caged compartments for prisoners, who are provided with little fresh air, no showers, and only limited access to food or a toilet.
The transfers can take days, weeks, or even months as the trains stop and convicts spend time in transit prisons. Convicts often face humiliation, beatings, and sometimes even death at the hands of their guards or other convicts.
Harsh rules dating back to Soviet times provide for the prisoners' families and lawyers being informed about their whereabouts only after they have reached their destination.
Navalny, 47, has complained of a concerted campaign of harassment and mistreatment since his imprisonment, including sleep deprivation, repeated stints in punishment cells for minor alleged infractions, and a lack of medical care.
He has been recognized as a prisoner of conscience by Amnesty International and listed as a political prisoner by Russia’s banned Memorial human rights group.