BELGRADE, Serbia — Serbia’s Russia-friendly leader made a surprise visit to Ukraine on Wednesday for a summit on strengthening European support for Kyiv’s fight against Russian aggression, but he refused to sign a joint declaration calling for tougher sanctions against Moscow.

Russia attacked the frontline Ukrainian regions of Kharkiv and Kherson with artillery fire, guided bombs and drones, killing three people and injuring at least 68.

Ukrainian officials say three people were killed and 13 were wounded when Russia attacked the country with waves of drones and missiles.

Russian forces have launched a large-scale drone assault across Ukraine, where officials said three people were killed and 64 others wounded

Russian forces have advanced into Dnipropetrovsk and Sumy regions, in fresh bid for Ukrainian land beyond what Moscow's already annexed.

Apart from drones, 20 missiles of various types were fired at different parts of Ukraine, according to the air force, which said the barrage targeted mainly central and western areas of Ukraine.

The preeminent body tracking alleged Russian war crimes in the war with Ukraine, including the abduction of Ukrainian children, has transferred its data to Ukraine’s government and the US State Department as it prepares to shut down in the coming weeks after the Trump administration terminated its funding.