Russia's Ministry of Defense went up in flames on Sunday, sending clouds of smoke billowing over Moscow. The cause of fire is still under investigation, but initial reports in Russian media have suggested it was accidental.

Major-General Igor Konashenkov told Russia's Interfax news agency that parts of the building in the Russian capital were still smoldering hours after the fire was extinguished. The building was evacuated of about 50 people, and no injuries were reported.

Russia's Ministry of Emergency Situations reported that the fire covered an area of at least 50 square meters. Video and photos taken at the scene earlier in the day showed firefighters climbing ladders up the building's exterior to reach the upper floors. Russia's Sputnik news agency said the building's roof had caved in.

SputnikInt: Roof of mod_russia building in Moscow caves in following blaze — Anonymous (@CovertAnonymous)April 3, 2016

Interfax, quoting a source, reported that the fire might have started due to an electrical malfunction, likely a short circuit involving old wiring.

The Defense Ministry told Interfax the fire would not hamper its operations.

The Ministry building was constructed in the 1940's and later renovated in the 1980s. The National Defense Management Center oversees operations in the building, which is the highest command center for Russian armed forces. The current Minister of Defense is Sergey Shoygu.