German Chancellor Angela Merkel and Ukrainian President Petro Poroshenko held talks in Kyiv on Saturday over the ongoing crisis in the country.
Merkel said the standoff over Ukraine could be solved but only if control of its border with Russia was tightened.
Speaking on the eve of Ukraine’s Independence Day celebrations,she proposed a deal between Kyiv and Moscow on monitoring of the frontier by the OSCE.
Poroshenko and his Russian counterpart Vladimir Putin will meet in Belarus on Tuesday, their first encounter since June.
Hours before Merkel’s arrival, heavy artillery bombardment in Donetsk, the main separatist stronghold in eastern Ukraine, resulted in the deaths of at least six people, according to local authorities.
A history museum and the stadium of Ukrainian football champions, Shakhtar Donetsk, were damaged by the shelling on Saturday.
Earlier, all the lorries from an unauthorised Russian aid convoy crossed back over the border from Ukraine. The move to enter the country had been heavily condemned by the West.