Russian forces are advancing in Ukraine at the fastest rate since the early months of the war, according to a respected US-based thinktank. Battlefield reports indicate Moscow is edging closer to the key logistics town of Pokrovsk in Donetsk.

The Kremlin warns that Washington's decision to let Ukraine strike targets inside Russia with U.S.-supplied longer-range missiles would stoke the war and escalate international tensions.

Russian authorities have ordered a British diplomat to leave the country on allegations of spying as tensions soar over the conflict in Ukraine