Russian President Vladimir Putin's principal opponent Alexei Navalny was briefly hospitalised Thursday after being hit in the eye by green dye that he said had damaged his cornea.
"Shrek 2: now one-eyed," he wrote on his blog alongside a picture showing his face spattered and one eye half-shut.
"At the hospital they wrote: 'Chemical burn to the right eye" + it's pretty unpleasant: it's hard to anaesthetise, my eye burns from the fire of hell and I cannot open it," Navalny added.
The opposition leader's spokeswoman Kira Larmych told the Interfax news agency that Navalny went to hospital after the dye attack outside a building in central Moscow damaged his pupil and cornea.
Navalny was struck by similar green dye in an attack last month.
A populist with nationalist anti-immigrant views, he has announced that he intends to stand in 2018 presidential polls that Putin is expected to contest for a fourth term.
Navalny faces legal obstacles to running for the top job due to a fraud conviction at a trial this year that would bar him from public office.
The 40-year-old rose to fame with fiery speeches at mass protests over Putin's return to the Kremlin for a third term in 2012. He has harnessed the power of social media and YouTube to spread his message.
He called the biggest opposition protest in Moscow in years last month, following his report on alleged luxury properties controlled by Prime Minister Dmitry Medvedev through shadowy foundations.
The gathering -- and other smaller ones around the country -- ended with around 1,000 arrests.