KYIV, Ukraine — Ukrainian President Volodymyr Zelenskyy urged supporters Saturday to speak out in defense of new U.S. sanctions against Russia, hours after President Donald Trump signed an executive order pausing a sweeping package of restrictions targeting the Russian economy.

The White House decision has further raised fears that Ukraine could be left exposed to Moscow's escalating assaults with winter approaching.

Russian attacks overnight killed at least four people, including an ambulance driver, and wounded dozens, officials said. Ukrainian drones killed a woman in a Russian border region and disrupted flights at Moscow's airports, according to Russian authorities.

In a statement on social media, Zelenskyy described Trump's move to put sanctions on hold as unfortunate, but did not directly criticize the U.S. leader despite deepening tensions between Ukraine and Washington in recent days.

"A decision was unfortunately made in America to completely disregard the Lindsey Graham Act, which was supposed to impose truly effective pressure on Russia to bring this war to an end," Zelenskyy wrote.

Later, in audio clips answering journalists' questions, Zelenskyy thanked Democrats and Republicans who backed the legislation and praised its bipartisan support. He said blocking it would encourage Russia to continue killing and do nothing to bring the war to an end. He also added that limiting Ukraine's ability to retaliate against Russian attacks would not bring peace.

"Nevertheless, we very much hope — and I personally hope — that the president of the United States of America will do everything possible to make Putin stop the killing, stop the attacks on our energy infrastructure, and end this war," he said.

Named after late South Carolina Sen. Lindsey Graham, the legislation had sought to clamp down more quickly on the flow of financial resources fueling Russia's 4 1/2-year-old war against Ukraine. The bill had sought to sanction Russian officials, banks and a shadow fleet of tankers that keeps Russian energy moving.

Trump personally signed the legislation just last month and his move came just two days before a deadline set in the law itself for its implementation. The president told Congress that the pause was in the national interest but gave no further details.

Sen. Richard Blumenthal, who co-drafted the bill, said in a statement that Trump was turning his back on "the majority of Americans, their representatives in both houses of Congress, and our European allies." "These waivers have nothing to do with our national security, and everything to do with sucking up to Vladimir Putin," Blumenthal said.

Trump's unexpected decision comes a week after he stunningly said the U.S. had agreed to purchase diesel from Russia to try to bring down global energy prices, despite that potentially hurting Ukraine in its war with Russia.

Trump said Russia would immediately supply more than 300,000 tons of diesel, followed by an additional 500,000 tons in November and 1 million tons "immediately thereafter." The decision has been pilloried by Republicans and Democrats alike who say it will help Russia execute its war against Ukraine — without making a difference to global fuel prices, which are elevated mostly due to Trump's war on Iran.

Zelenskyy also said Saturday that Moscow had carried out a massive strike on Ukraine's energy infrastructure, targeting more than 15 sites across the country.

Russia's heavy bombardment of the power grid ahead of winter has been an annual feature of the war, aimed at wearing down Ukraine's appetite for the fight by denying civilians heat and running water. Ukrainian officials have warned that Russia is stockpiling ballistic missiles for more attacks in the coming months.

Russian attacks killed three people in the Ukrainian city of Sloviansk, Vadym Liakh, head of the city military administration, said Saturday. Writing on social media, Liakh said that two apartment blocks were partially destroyed and other homes damaged.

A Russian strike also killed an ambulance driver in Ukraine's Kherson region, head of the local military administration Yaroslav Shanko said. The strike, which used guided bombs, wounded at least 33 others, he said.

Elsewhere, a Russian woman was killed in a Ukrainian drone attack in the Russian border region of Belgorod, local officials said.

Russia's Ministry of Defense said Saturday that its forces had shot down 610 Ukrainian drones overnight over 15 Russian regions, as well as the annexed Ukrainian peninsula of Crimea and the Black Sea.

Moscow Mayor Sergei Sobyanin said that more than 100 drones were shot down en route to the Russian capital. More than 350 flights were canceled or delayed at Moscow's airports, local media reported, as planes were grounded in response to incoming drones.

The Kremlin announced Saturday that Russian President Vladimir Putin had approved a government program to help restore trade and logistics facilities damaged in drone attacks.