The 35 sect members, including 4 children, went into the cave in November to "save themselves during the time of the Apocalypse," which they say is due in May. They have threatened to set themselves on fire if any attempt is made to remove them from the cave by force.
"Local administration officials held talks with the sect members and, in contrast to other, earlier negotiations, these proved successful. They have agreed to come out of their voluntary confinement and have named several dates. They might come out on April 27 - Orthodox Easter - or during the May holidays [May 1-9]," the spokesman said.
It is not clear how this promise ties in with the group's belief concerning May and the destruction of the planet.
According to the spokesman, the sect's leader, Pyotr Kuznetsov, was involved in the talks. No further details were given, however.
Kuznetsov, 43, has been held in an asylum in Penza, about 600 km (370 miles) southeast of Moscow since November. On Wednesday, he was declared mentally unfit to stand trial. He had earlier been charged with inciting religious and racial hatred.
"It's possible that the sect members realized that their lives could be in danger if they remained underground due to the spring thaw. They have had to urgently strengthen the walls of the cave recently," said the spokesman, adding that large lumps of soil had also fallen into the sect's 'home'.
The cave is said to have been divided into five cells, with one large area set aside for prayers.
Kuznetsov has not explained why he did not go underground with his followers.
Various groups had earlier spoken to the sect members without managing to secure a promise that they would come to the surface. A local official earlier said that the main aim of the psychiatrists and religious leaders who had been negotiating with the sect was to convince the group to allow their children to leave the cave. However, he said, the sect's response was that, "The children have suffered enough in this world. You are talking about their bodies, but we are speaking of their souls!"
Police have repeatedly denied that they were planning to storm the cave to try and rescue the children involved.
