( CNN ) -- Doctors are fighting to save the sight of the artistic director of Russia 's illustrious Bolshoi Ballet after a masked assailant threw acid in his face on a Moscow street , state media reported . Sergei Filin , 43 , was approaching his home around midnight Thursday when the unidentified attacker flung the concentrated acid at him , causing severe burns to his face , the state-run news agency RIA Novosti reported Friday . It could take Filin at least six months to recover from the third-degree burns to his face and eyes , RIA Novosti cited Yekaterina Novikova , a Bolshoi spokeswoman , as saying . Filin took up the key role at the world-renowned ballet company in 2011 , after three years directing Moscow 's Stanislavsky and Nemirovich-Danchenko Music Theater . There was `` fierce rivalry '' for the Bolshoi position at the time , according to RIA Novosti . The agency reported that Filin had suffered months of intimidation , including threatening phone calls and the slashing of his car tires . Shortly before the acid attack , somebody attempted to hack his Facebook page , it said . `` We do n't know who would benefit from this , '' Novikova told RIA Novosti . `` The police should investigate . ''
Sergei Filin was attacked as he approached his home in Moscow on Thursday night . The unidentified assailant threw concentrated acid in his face , causing severe burns . Filin had suffered intimidation , including threatening phone calls , state media say .