The conflict in eastern Ukraine escalated as Ukrainian troops launched a new assault on the Russian-held city of Bakhmut, killing two senior Russian officers.
Russia also lost four aircraft and two helicopters that were shot down by Ukrainian air defences before crossing the border.
Ukrainian President Volodymyr Zelenskyy visited Berlin and received strong backing from German Chancellor Olaf Scholz, who pledged to support Ukraine “for as long as it is necessary”.
Zelenskyy said he and his allies could make Russia lose the war this year if they increased their pressure on Moscow.
The G7 leaders are expected to announce tougher sanctions on Russia at their meeting in Japan, targeting its energy and export sectors.
Germany and France also announced more military aid for Ukraine, including tanks, antiaircraft systems, armoured vehicles and ammunition.
The EU’s top diplomat Josep Borrell urged faster delivery of ammunition to Ukraine, saying its forces needed 1,000 shells per day in Bakhmut alone.