Russia has carried out another wave of attacks across Ukraine, including on a scientific institute in the capital Kyiv.
The National Academy of Sciences is in the heart of Kyiv and not far from the German embassy.
It comes as a top US general tells Europe Russian efforts to intimidate them through hybrid warfare are failing to weaken support for Ukraine.
Russian drones have struck Ukraine's National Academy of Sciences in the heart of Kyiv, in the latest fatal daytime attack on the Ukrainian capital.
Kyiv has faced Russian drones and missiles as Europe's worst conflict since World War II grinds through its fifth year.
Video footage shared online appeared to show a high-speed drone smashing into the National Academy of Sciences at a sharp angle, exploding and sending acrid smoke into the blue sky above.
Ukraine's former national security and defence council secretary Volodymyr Gorbulin told state broadcaster Suspilne that he was at work at the academy at the time and was wounded.
But he said his assistant, who was near the building, was killed.
The National Academy of Sciences is close to the German embassy, a cathedral, the national opera and government buildings.
Elsewhere, Russian strikes killed four and wounded at least 19 at a business centre in the central city of Dnipro while authorities reported an unspecified number of fatalities in a strike on a residential area in eastern Kharkiv.
Prime Minister Sergiy Koretsky said Russian forces damaged an ice cream factory in the Zhytomyr region west of Kyiv, and residential buildings in Sumy, in the north, Rivne, in the northwest, and southern Odesa.
Thirty civilians were wounded, three of them seriously, in strikes on Zaporizhzhia, southeastern Ukraine, the regional military administration said.
During Russia's assault, Poland moved jets to defend its air space and warned citizens near the Ukrainian border to stay inside.
The strikes comes as Ukrainians consider their options with winter approaching, after Russian attacks last year on energy infrastructure cut power and heating as temperatures fell to as low as -20C.
Meanwhile, European defence ministers discussed whether the European Union needed its own NATO-style emergency mechanism to bolster coordination against "hybrid attacks" by Russia.
European governments say Moscow is stepping up its campaign of sabotage and interference against Ukraine's supporters, as Kremlin troops struggle to make headway on the front lines.
That came as NATO's top military commander said that Russia's sabotage campaign in Europe was failing to put countries off supporting Ukraine.
"State-directed sabotage is growing increasingly brazen," US General Alexus Grynkewich, NATO's Supreme Allied Commander Europe, told a committee of EU politicians.
General Grynkewich cited recent incidents including the discovery of an explosive-laden drone at a German airport and a Russian naval ship firing flares at a Danish helicopter.
"These are clear examples of attempts to instil fear and fracture our unified support to Ukraine. It isn't working," he said, pointing at Denmark's fast-tracking of fresh aid for Ukraine after the flare incident.