Russia's FSB security service on Thursday accused top allies of jailed Kremlin critic Alexei Navalny of inciting a bomb attack that killed a high-profile military blogger.
The explosion ripped through a cafe in Saint Petersburg, killing 40-year-old blogger Vladlen Tatarsky and wounding dozens.
Investigators have accused Ukraine and members of Russia's embattled opposition of being behind the blast and a 26-year-old Russian woman, Darya Trepova, was detained and charged with terrorism.
Investigators accuse Trepova of bringing a statuette rigged with explosives to a cafe in Saint Petersburg where Tatarsky was meeting with supporters.
In a statement on Thursday, Russia's domestic security service, the FSB, singled out two of Navalny's closest allies -- Leonid Volkov and Ivan Zhdanov.
The security service claimed that Navalny's aides had inspired Trepova to carry out the bombing attack.
The FSB said Trepova supported "Navalny's ideology" including a "Smart Voting" strategy to defeat Kremlin-aligned politicians in elections.
The statement also pointed out that the woman accused of the attack is represented by Daniil Berman, who is the lawyer for other Kremlin critics as well as espionage-accused US journalist Evan Gershkovich.
Zhdanov, head of Navalny's Anti-Corruption Foundation, suggested Russian authorities were gearing up to formally recognise the outfit a "terrorist" organisation.
Navalny's offices in Russia were already labelled extremist and outlawed in 2021.
Zhdanov said he doubted that Trepova had known about the contents of the statuette and claimed that "millions of people" hated President Vladimir Putin.
"I am indeed an enemy of this regime," he said in a statement on Telegram.
He called Putin and his allies "the worst criminals: murderers, bandits, terrorists and fascists."
The FSB claimed it had established that Yury Denisov, a Ukrainian member of a "sabotage and terrorist group", helped Trepova target the blogger by sending her explosives.