Russia suffered a huge blow when a fuel tank explosion on early Saturday caused part of Europe's longest bridge that links Russia to the annexed territory of Crimea to collapse.
Russian President Vladimir Putin immediately ordered a "government commission" to examine the Kerch Bridge "emergency" in Crimea, Russian state media TASS reported.
The heads of Russia's Ministry of Emergency Situations and the Ministry of Transport are now at the scene of the incident, according to TASS.
Images of the Kerch bridge posted on social media appear to show a portion of the roadway of the vehicle and rail bridge had fallen into the waters below it. Flames are seen burning from rail cars above.
The tanker was located on the 19-kilometer (11 mile) long bridge -- strategically important because it links Russia's Krasnodar region with the Russian-annexed Crimean Peninsula.
The bridge spans the Kerch Strait, which connects the Black Sea to the Sea of Azov, on which sit key Ukrainian ports, including Mariupol. The source of the explosion remains unclear.