Activist said the car wash is owned by a man known to be part of pro-government militias known as the shabiha.

The Moscow police have stepped up security across the city in preparation for the opposition March of Millions rally.

The next European Athletics Indoor Championships are scheduled to be held between March 1 and 3, 2013.

“The timing of his arrest also coincides with a crackdown on Shiite Muslims and Iranian sympathizers,” the group says.

“There is no other inflammable gas which would have a lift capacity; this was either methane or hydrogen,” Vladimir Fedotov said.

Three days earlier, a suicide bomber killed nine, including security men, at a Damascus mosque, the Interior Ministry said.