A massive fire broke out early Sunday on a gas pipeline in the southeast of Moscow, sending flames 200 metres (600 feet) into the sky, local officials said.
Moscow mayor Yuri Luzhkov said that five people had been injured in the fire, including one man who received 35 percent burns, but there had been no fatalities, the Interfax news agency reported.
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," he added, according to the RIA Novosti news agency.
"I don't remember there ever being a fire like this in Moscow," added deputy mayor Petr Birukov.