Deputy Interior Minister Vitaly Mozyakov, who is leading the investigation into last night's explosion at a block of flats on Moscow's Akademika Korolyova Street, told journalists on Wednesday that two possible causes were being considered: a gas explosion or a terrorist act.
According to him, "no one version has been confirmed so far, as experts have not begun their direct work," because not all the rubble has been cleared yet.
Mozyakov also said that a special investigation group, including representatives of the Interior Ministry, the Federal Security Service and the Prosecutor's Office, had been set up to examine the circumstances of the incident.
According to the latest information, seven people fell victims to the explosion, while rescuers believe that a further 10-12 people could be still under the rubble.
The explosion tore through the block of flats late last night.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969