KYIV, Ukraine — Russia fired more than 500 drones and two dozen missiles at Ukraine overnight, authorities said Wednesday, as Ukraine’s president and European leaders persevered with talks aimed at strengthening Ukrainian defenses and adding momentum to so far unsuccessful U.S.-led peace efforts.

The main Russian nighttime targets were civilian infrastructure, especially energy facilities, Ukraine President Volodymyr Zelenskyy said, as another winter approaches three years after Russia’s all-out invasion of its neighbor. The attacks targeted mainly western and central Ukraine and injured at least five people, the Ukrainian air force said.

Russian aerial assaults that hit civilian areas and the Russian army’s drive to crush Ukrainian defenses along the 1,000-kilometer (620-mile) front line have not abated in recent months, despite U.S. President Donald Trump’s attempts to stop the fighting.

While Zelenskyy has accepted Trump’s proposals for a ceasefire and face-to-face peace talks with Russian President Vladimir Putin, the Kremlin has raised objections.

Amid recent diplomatic maneuvering, Putin was in China meeting with Chinese leader Xi Jinping and North Korean leader Kim Jong Un, as well as Indian Prime Minister Narendra Modi. Those countries are supporting Russia’s war effort, Washington says. Pyongyang has sent troops and ammunition to Russia. China and India have bought Russian oil, indirectly helping Russia’s war economy.

Zelenskyy described the overnight strikes as “demonstrative.”

“Putin is demonstrating his impunity,” Zelenskyy said on Telegram, urging tougher sanctions on Russia. “Only due to the lack of sufficient pressure, primarily on the war economy, does Russia continue this aggression.”

In his daily video address on Tuesday evening, Zelenskyy said the number of Russian drone attacks is growing, including in broad daylight, and reported “another buildup of Russian forces in some sectors of the front.”

Zelenskyy arrived in Denmark on Tuesday for talks with Northern European and Baltic countries about new military aid and further diplomatic support for Ukraine.

British Defense Secretary John Healey, meanwhile, arrived in the Ukrainian capital Kyiv for meetings on how to strengthen Ukraine’s military.

Zelenskyy was due later Wednesday in Paris for talks with French President Emmanuel Macron, ahead of a Thursday meeting there of European countries assessing what kind of postwar security guarantees they might be able to provide with the United States.