The followers of self-declared prophet Pyotr Kuznetsov went into a cave about 640 kilometers (400 miles) southeast of Moscow earlier this month and have threatened to blow themselves up if forced to leave. They say they believe the world will end in May.
Kuznetsov had agreed earlier to talk to his followers Wednesday and seek the release of the four children in the group, the youngest of whom is 18 months old, said Yevgeny Guseynov, a regional government official. But he later refused to do so, Guseynov said.
"He changed his mind or maybe he lied in the first place," Guseynov said.
He said authorities would try again to convince Kuznetsov to coax his followers out, or at least to let the children go, but said everything depended on Kuznetsov's psychological state.
"We will wait when his state of mind allows it," Guseynov said.
Kuznetsov is now confined to a psychiatric hospital. He was charged last week with setting up a religious organization associated with violence.
Kuznetsov, 43, an engineer from a devout family, declared himself a prophet several years ago. He left his family and established the True Russian Orthodox Church and recruited followers in Russia and Belarus.
Kuznetsov reportedly told followers that, in the afterlife, they would be judging whether others deserved heaven or hell. Followers were not allowed to watch television, listen to the radio or handle money, reports say.