MOSCOW – Russia's Bolshoi ballet named a top ballerina as acting chief Tuesday after its artistic director underwent surgery to treat severe burns to his face from a horrific acid attack.

The temporary shift in command at one of Russia's most venerable institutions follows a still-unsolved incident that left 42-year-old Sergei Filin at risk of losing his eyesight.

The Bolshoi said its board of directors and Russia's culture ministry agreed to tap 46-year-old veteran ballerina Galina Stepanenko as its acting artistic director.

Stepanenko is a stalwart of the Bolshoi who has danced all the great ballerina roles in the classical repertoire since first joining the company in 1990.

"We are all shattered by what happened and it is not easy for us. We need to be together and keep working," Stepanenko said after the announcement of her appointment -- recommended by Filin himself.

She is to remain in the post until Filin is well enough to return to work.

The theatre has blamed the Thursday evening attack on internal conflicts although investigators have yet to make any conclusions or arrests.

The overall head of the Bolshoi admitted that he had his own list of suspects but was not prepared to make them public.

"Of course I have my ideas and most in the troupe have their ideas (about who organized the attack)," the Bolshoi's general director Anatoly Iksanov told state television.

"I cannot just come out and say it because I might be wrong -- although there are specific suspicions about specific people," he said.

"The mood in the theatre is not joyous," Iksanov said. But the company went ahead with the first stage rehearsal for Thursday's premier performance of "La Bayadere" on its historic stage.

The violent incident has shaken the global ballet community and cast a spotlight on rivalries raging between superstars of the 237-year-old institution -- one of Russia's most prominent brands.

Police have already spoken to several Bolshoi staff as they sift through allegations that the attack was triggered by either personal rivalries or criminals with links to the globetrotting troupe.

Filin himself underwent a high-tech procedure Tuesday to remove lesions from the third-degree burns he suffered when cornered outside his home by the single hooded assailant.

"The operation was a success," the Moscow city health department said in a statement.

Filin -- a photogenic principal dancer who became artistic director in 2011 -- said in his first detailed hospital interview that he made the mistake of not alerting the media about an earlier spate of death threats.

"The only thing I blame myself for is carelessness," he added. "I should have told the media about the threats right away, before New Year."

Friends said that Filin had told them about his car tires being slashed and his social networking account being hacked -- and its explicit content republished -- within the past few weeks.

He also reported getting repeated prank phonecalls late into the night.

Filin named no suspects in the interview while also hinting that he knew where the trouble was coming from.

He told the paper that "a single decision" at the top could have ended both the infighting and threats against his life.

Doctors said the assailant threw the sulphuric acid cocktail on the right side of Filin's face and that his left eye was recovering vision more quickly as a result.

The dancer admitted that the best his left eye could do for the moment was allow him to "sometimes... see all the fingers on my hand."

"I have three sons," he added. "I want to see how they grow up and get up on their feet."

The burns forced Filin to undergo an emergency eye operation on Friday. A second such procedure has been scheduled for Wednesday.

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