Rescuers, who continued to dig through rubble all night in freezing temperatures in the search for survivors, found 20 bodies, four of them children, officials were quoted by the ITAR-TASS news agency as saying.
One more man died of his injuries in hospital.
However, the spokesman for Moscow's mayor, Yuri Luzhkov, gave the toll as 18, the RIA-Novosti news agency reported.
Of the 110 people rushed to hospital, 90 remained in medical care, four of them in a critical condition, officials said earlier, adding that 25 children had been treated in hospital.
Emergency ministry officials said rescue workers were still hearing cries for help from under the wreckage of the giant Aqua Park, several hours after its roof collapsed late on Saturday. They believe up to 15 preople could be trapped in the rubble.
Three children were among the bodies recovered.
"The rescuers are guided by people's voices and their calls for help sounding from these spots. Periodically, once in half an hour, minutes of silence are observed in order to locate the victims under the wreckage," an official said.
Sniffer dogs were brought in to help in the search, but were unable to work because of excessive steam.
The glass roof is reported to have collapsed under the weight of snow.
The collapse made top news on Russian television because of persistent fears that insurgents from separatist Chechnya are planning attacks against civilian targets in the run up to 14 March presidential elections.
The roof reportedly collapsed
under the weight of snow
About 420 people were reported to be in the area where the roof caved in and a total of 1300 visitors were in the complex, Luzhkov said.
Police later ruled out an explosion, despite initial speculations about a blast.
Moscow has been rocked by a series of attacks blamed on suicide bombers from the breakaway republic of Chechnya that have jittered nerves across the country.
"It has been definitely confirmed it was not an act of terror," Luzhkov said.
No foul play
Several dozen ambulances rushed to the scene, along with fire trucks, paralysing traffic in Russia's bustling city on the
Rescuers carry an injured bather
from the pool
News agencies later quoted emergency ministry officials as saying they did not suspect foul play.
"There was no blast," ITAR-TASS quoted emergencies ministry spokesman Viktor Beltsov as saying.
The news agency separately quoted an emergencies ministry
official as saying the incident "was not an act of terrorism".
Fourteen ambulances attended the scene to treat the injured.