A gas pipeline exploded in southwest Moscow early on Sunday, sending flames 100 metres into the air and setting buildings and cars ablaze.
Emergency service officials said about 35 firefighting teams were sent to extinguish the fire.
The flames were visible for many kilometres. Russian agencies reported that they spread to two buildings and several cars. The closest homes to the fire are more than 500 metres away, putting them out of its reach, an official told RIA news agency.
Moscow's mayor Yuri Luzhkov said that five people had been injured in the fire, including one man who received 35% burns, but there had been no fatalities.
He added that the cause of the fire was almost certainly to be technical in nature.
"The cause could have been an upsurge of pressure in the pipeline, as a result of which an explosion took place underground," Mr Luzhkov added.