At least one person has been killed and two injured in a fire at a building used by Russia’s Federal Security Service (FSB) in the southern city of Rostov-on-Don, Russian media say.
Dramatic footage on social media shows a large blaze, with smoke visible all over the city.
Rostov’s regional governor said a short circuit appeared to have caused the fire, which ignited fuel tanks.
The street where the building is located has been cordoned off.
The blaze occurred at a building belonging to the FSB’s regional border patrol section in a built-up area of the city.
The FSB is Russia’s internal security service and is responsible for counter-intelligence, border security and counter-terrorism.
Rostov Governor Vassily Golubev said the fire had spread over 800 sq m, causing two walls to collapse.
He said there was no threat that the fire would spread but that residents of nearby blocks of flats were being evacuated as a precaution.
RIA news agency said quoting emergency services that the area on fire was a two-storey building used for garages and storage.
Rostov-on-Don is the capital of a southern Russian region bordering on the Donetsk and Luhansk regions of Ukraine, currently the scene of intense fighting in the war.
There have been a spate of arson attacks on government buildings in Russia, such as enlistment and conscription offices, since the February 2022 invasion of Ukraine.
Ukraine denied involvement in the fire.
Presidential aide Mykhaylo Podolyak said on Twitter that the incident was a “manifestation of panic” in Russia. “Ukraine doesn’t interfere, but watches with pleasure,” he said.