Vladimir Putin's principal opponent Alexei Navalny has accused the Kremlin of being involved in a green dye attack which he said damaged his cornea.

Russian network REN-TV published a video of Thursday's attack on the opposition leader in which the face of the assailant is blurred.

The video, first broadcast on Friday, starts as Mr Navalny bends down and raises a hand to the right side of his face covered by the green substance believed to be the Soviet-era topical antiseptic known as "zelyonka.".

The attacker is filmed as he runs away from Mr Navalny and towards the camera, however in the broadcast video it's impossible to discern his face as it is heavily pixellated.

On Sunday, Mr Navalny suggested on Twitter that the video was leaked to the Kremlin-friendly private broadcaster by authorities and accused Russia's FSB (Russia's Federal Security Service) of involvement.

"They have no shame," Mr Navalny wrote in a tweet.