Small groups of Russian troops have pierced parts of Ukraine’s defenses in its eastern Donetsk region, according to local officials, as Russia appears to be making an 11th-hour dash to snatch as much territory as possible ahead of the planned meeting between President Vladimir Putin and his US counterpart Donald Trump on Friday.

Russian forces have made a sudden thrust into eastern Ukraine near the coal mining town of Dobropillia, a move that may be an attempt to increase the pressure on Kyiv to give up land as the U.S. and Russian presidents prepare to meet.

Russia's advance in the east has resulted in Ukraine shifting some of its most experienced troops there in an attempt to blunt it.