A pair of Russian opposition activists have been partially blinded by acid attacks in just two days.
The incidents have fuelled fears that a reported clampdown on political resistance in the country is escalating.
Unknown assailants threw green dye in lawyer-turned political activist Alexei Navalny's face on Thursday, resulting in chemical burns to his right eye, independent television network Dozhd reported.
Mr Navalny's Anti-Corruption Foundation investigates the wealth of President Vladimir Putin's inner circle.
The next day, Natalia Fyodorova, a Moscow-based activist for the Russian opposition party Yabloko, suffered burns to her eyes after an assailant splashed her with a chemical as she was leaving her house.
The head of the Yabloko's Moscow branch told independent news agency Interfax that she had lost vision, but may regain her sight with time.
Mr Navalny, one of the foremost Russian critics of President Vladimir Putin who has announced his intention to run for president himself, blamed the Kremlin for the attack.
After a video of the attack surfaced on the REN TV website – a pro-government television channel – Mr Navalny wrote on Twitter: “This is the best proof that the FSB and the [Presidential Administration] were also involved. [It’s their] trademark style.”
Authorities have denied having any connection to the attacks.