The head of the Russian-American joint venture Yamal denied any involvement Tuesday in an attack on the theater director Leonid Kheifets, who was beaten up, threatened and robbed last weekend by four unidentified men who pushed their way into his apartment.


Valery Sokolov, general director of Yamal, which had signed a deal to lease Kheifets' Russian Army Theater, told a press conference that the company enjoyed good relations with the director, despite his opposition to the leasing deal.


"We worked with him very closely and we did not have contradictions with him," Sokolov said. "We were shocked and outraged when we heard about the incident."


Kheifets was attacked last Friday morning. His assailants took $3,000 and called by telephone later in the day to demand more money and to warn him against setting foot in his theater again.


"There is no truth whatsoever in mass media reports that this company was involved in the incident," Sokolov said. "It is just a lie."


Oskar Kuznetsov, deputy head of the theater, said at the same press conference that relations between Kheifets and the company had become "strained" when the director had found out about the details of the rental deal.


The deal envisaged renting out the theater for the period of 25 years for Yamal to stage shows, using actors from other theaters, he said.


"Kheifets told me he did not have the right to determine the fate of the theater for such a long period," Kuznetsov said.


Oksana Kryukova, a spokeswoman for the Culture Ministry, said by phone that 15 leading Russian directors and actors had sent an appeal to President Boris Yeltsin, the Federal Counterintelligence Service and the Interior Ministry to investigate the incident "immediately."


The appeal said Kheifets and members of his family, including his wife, 8-year-old daughter and 86-year-old mother, were relying on friends to protect them, without any support from law-enforcement organs.