Yury Sedelnikov, the head of the Emergency Situations Ministry Moscow department, said the rescue operation was nearly over. "The whole facility has been searched. No more dead bodies have been found yet, and we hope no more [dead bodies] will be discovered," he said.
Earlier, some ministry officials put the death toll at 50.
President Vladimir Putin said the incident should be thoroughly investigated.
Emergency Situations Minister Sergei Shoigu heads the rescue operation, which involves some 500 rescuers. He said the collapse of some 13,000 square meters of the roof had probably been caused by a construction defect.
Andrei Legoshin, a ministry official, said the market roof collapse resembled a similar tragedy in Transvaal Park building in Moscow that collapsed two years ago killing 28 and injuring more than 100. Transvaal Park was designed by the same architect as the Basmanny market - Nodar Kancheli.
Legoshin said some 60% of the debris had been cleared as of 19.00 Moscow time (4 p.m. GMT). He did not rule out some more bodies or survivors could be found under the rubble.
Moscow mayor Yury Luzhkov, who arrived at the site of the tragedy that mainly affected non-Muscovites, told journalists that the roof collapse had not been a terrorist act. He said it could have been caused by heavy load of snow accumulated on top of the building. "The possible cause [of the collapse] is the excessive amount of snow gathered on the roof, which has a concave shape," the mayor said. However, he said the load on the roof had been within the prescribed limits.
He confirmed that after a tragedy at Transvaal Park in February 2004, all buildings designed by architect Nodar Kancheli had been inspected. The roof of the Basmanny market was designed to support heavy loads of snow and had special drainage systems, the mayor said.
Luzhkov said all buildings in Moscow with similar roofs should be inspected once again.
A criminal case was opened on the incident.
After being interrogated by the investigators in connection with the incident, architect Kancheli said it had occurred due to improper maintenance: many kiosks had been mounted on the entresol along the whole perimeter of the market, and the construction had not been designed for such additional load. He also said the accident could have been caused by excessive amount of snow. He added that the building had been opened in 1975.
The Moscow firefighting service said a small fire had occurred under the debris of the Basmanny market after the collapse, but that it had been put out and no one was hurt in the flame.