According to the Russian ambassador to the US, Moscow would view an American attack on a Russian aircraft in international airspace as a declaration of war.
The battle for Bakhmut has become the focus of Russia's winter campaign to capture Ukraine's eastern region, with both sides describing it as Europe's bloodiest infantry battle since World War Two.
Next week, a Turkish delegation will fly to the Russian capital for technical discussions ahead of a planned meeting of the foreign ministers of Turkey, Russia, Iran, and Syria.
U.S. President Joe Biden will meet leaders of NATO's eastern flank on Wednesday to show support for their security after Moscow suspended a landmark nuclear arms control treaty.
