Officials in Chechnya declined to answer questions about Kadyrov's status on Friday after 24 hours had passed without a sighting of the strongman president.
The Russian news service Tass, quoting unnamed medical sources, said Thursday that Kadyrov is under medical observation for suspected coronavirus infection and is in stable condition.
A similar report was published by the semi-official RIA Novosti.
Akhmed Dudayev, head of state-run Grozny TV, said in an Instagram post that Kadyrov was still in control of the country but did not explicitly deny the reports of his hospitalization.
The authoritarian Chechen leader is a key ally of Russian President Vladimir Putin and is widely condemned for his human rights record.
Since taking office as head of the semi-autonomous Chechen Republic in 2007 and imposing a modified version of Islamic law, human rights observers say Kadyrov has frequently used military and police forces to terrorize civilians, subjecting them to unlawful arrests, sexual violence, torture, enforced disappearances and killings.
Chechen authorities have consistently dismissed the allegations as untrue.