A Russian priest was reportedly arrested Saturday after announcing he would hold a public memorial service for Putin critic Alexei Navalny in St. Petersburg, Russia. 

Grigory Mikhnov-Vaitenko was reportedly detained outside his home while on his way to the Solovetsky Stone, a monument located in Moscow dedicated to victims of political repression, according to The Moscow Times. Mourners have continued to lay flowers in Navalny's memory after news of his death was announced. 

Mikhonv-Vaitenko's wife, Natalia Sivohina, also took to Facebook after the priest was reportedly detained. 

RUSSIAN DUMA SPEAKER ACCUSES US, EU, NATO AND OTHERS OF KILLING PUTIN OPPONENT NAVALNY

Navalny's spokesperson, Kira Yarmysh, declared Navalny was murdered via a social media post on X Saturday, one day after Russia’s prison agency announced his death on Friday. Navalny was being held at the IK-3 penal colony, also known as "Polar Wolf," in Kharp, Russia.

Navalny appears in Moscow court

Alexei Navalny's spokesperson, Kira Yarmysh, declared Navalny was murdered via a social media post on X Saturday, one day after Russia’s prison agency announced his death on Friday. Navalny was being held at the IK-3 penal colony, also known as "Polar Wolf," in Kharp, Russia. (AP/Alexander Zemlianichenko)

The agency said he felt unwell after a walk and lost consciousness. An ambulance arrived to rehabilitate him, but he died, per a statement released. Navalny was 47 years old. 

ALEXEI NAVALNY'S WIFE HAS A MESSAGE FOR PUTIN FOLLOWING NEWS OF HUSBAND'S DEATH

He had previously run for office to advocate for reforms against what he claimed was corruption in Russia. He also organized anti-government demonstrations and was the victim of an alleged assassination attempt in 2020, when he suffered poisoning from a suspected Novichok nerve agent.  

Russian opposition leader Alexei Navalny in court

Alexei Navalny had previously run for office in an effort to advocate for reforms against what he claimed was corruption in Russia.  (AP Photo/Alexander Zemlianichenko, File)

Navalny remained in a coma for several weeks while doctors in Germany fought to keep him alive. He accused Putin of being responsible for his poisoning. 

Alexei Navalny

Alexei Navalny had previously organized anti-government demonstrations and was the victim of an alleged assassination attempt in 2020, when he suffered poisoning from a suspected Novichok nerve agent.   (AP Photo/Alexander Zemlianichenko)

Navalny later returned to Russia in 2021. He was immediately arrested by authorities and later sentenced to 19 years in prison on extremism charges. His team has repeatedly raised concerns about his treatment following his return, and Navalny said the charges were politically motivated. 

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Fox News' Timothy Nerozzi and Greg Norman contributed to this report.