Small groups of Russian troops have pierced parts of Ukraine’s defenses in its eastern Donetsk region, according to local officials and monitoring groups, adding to Kyiv’s complications as Russia attempts to encircle the key strategic city of Pokrovsk.

Small bands of Russian soldiers thrust deeper into eastern Ukraine on Tuesday ahead of a summit this week between Russian President Vladimir Putin and U.S. President Donald Trump, which European Union states fear could end in peace terms imposed on an unlawfully shrunken Ukraine.

Moscow's forces are making gains near Pokrovsk in Ukraine's Donetsk region, according to the Institute for the Study of War.