A fire that ripped through a train as it travelled along a strategic rail tunnel in eastern Russia was the work of the Ukrainian Security Service (SBU), a Ukrainian defense source has claimed. “Four explosive devices were detonated while the freight train was in motion,” a source with knowledge of SBU operations told CNN. The explosion occurred on the Baikal-Amur railway, in the Bessolov Severomuyskiy tunnel in Buryatia, in the eastern Siberia region of Russia bordering Mongolia, according to the source. “The explosion is yet another successful special operation by the SBU,” the source said. The SBU has not officially commented on the incident. CNN cannot independently confirm explosions on the rail road. Russia has not immediately called this an attack or blamed Ukraine for what it has so far characterized as a “a cargo train fire.” Ukraine has for months been striking targets inside Russia, as it slowly tries to wear down domestic support for Moscow’s war. The Russian Railway reported a fire incident on a train along that route and said they are working on “eliminating the consequences of a cargo train fire in the Severomuyskiy tunnel,” in a statement posted to Telegram. The Ukrainian source characterized the route as “the only major railroad connection between Russia and China.” A prosecutor is in the area to coordinate the actions of law enforcement and supervisory authorities, according to a statement from the East Siberian Transport Prosecutor’s Office. “According to preliminary information, a wagon in a freight train caught fire at night on November 29, 2023 at the Itykit — Okusikan crossing of the East Siberian Railway while traveling through the Severomuisky tunnel. Recovery and fire trains were involved to eliminate the consequences of the fire. There were no casualties,” the prosecutors office said. Russian authorities “will take response measures based on the results of the inspection, in case there are grounds to do so,” the statement said. Train traffic has been rerouted, according to the Russian Railway. “Train traffic has not been interrupted along the route, it was organized on a detour route with a slight increase in travel time.” The rail provider said it was working to determine the extent of the damage. — CNN