They have threatened to detonate gas canisters should police attempt to remove them.
Dmitry Yeskin, a regional emergency spokesman, said on Tuesday that negotiators were trying to persuade the remaining people to leave the cave.
He said the group that came out on Tuesday handed over three rifles.
Priests from the Orthodox Christian church have tried to persuade the group to leave, communicating through a chimney pipe leading to the underground shelter.
Some of the cult members said last week that they might leave the cave on Orthodox Easter, which is April 27.
Pyoter Kuznetsov, the group's leader, has been charged with setting up a religious organisation associated with violence.
He was brought to Nikolskoye from a psychiatric hospital, where he had been confined since November, to help in negotiations with the people underground.
Kuznetsov, who goes by the title of Father Pyotr, declared himself a prophet several years ago and established the True Russian Orthodox Church.
He reportedly told followers that they would judge whether others deserved heaven or hell when they reached the afterlife.
Members are not allowed to handle money, watch television or listen to the radio, Russian media reported.