A court in Russia ruled to keep Alexey Navalny in custody for 30 days, the opposition figure's lawyer Vadim Kobzev said Monday.
"Alexey Navalny is arrested for 30 days until February 15, 2021," Kobzev tweeted.
On 29 January, another court in Moscow is expected to decide whether Navalny's suspended sentence should be left in place or replaced with prison time.
Navalny's defence team has stated that they will challenge the arrest of the opposition figure in the Moscow Regional Court.
"Of course, this decision will be appealed. We consider it absolutely illegal", Navalny's lawyer Vadim Kobzev told Russia’s Interfax news outlet.
Russian opposition figure Alexei Navalny arrived in Moscow on Sunday for the first time since late August after he was allegedly poisoned and sent to Germany, where he underwent medical treatment.
Prior to Navalny's return, the Russian Federal Penitentiary Service warned it would detain him for what it called "probation violations" because he was previously found guilty of committing two administrative offences.
Navalny fell ill aboard a domestic Russian flight on 20 August. He was initially treated in the Siberian city of Omsk after the plane made an emergency landing. Local doctors suggested a metabolic malfunction as the main diagnosis and stated that there were no traces of poison in his system.
In September 2020, Navalny was discharged from the hospital. Moscow has called on Berlin to present the biological materials to corroborate the chemical poisoning so that it could open a criminal case.