By ILLIA NOVIKOV, Associated Press

KYIV, Ukraine (AP) — Clinching a deal to end the Russia-Ukraine war “is far too complex to be done quickly,” a senior Kremlin official said Wednesday, as the U.S. labors to bring momentum to peace efforts and expresses frustration over the slow progress.

Meanwhile, a nighttime Russian drone attack on Ukraine’s second-largest city of Kharkiv wounded at least 45 civilians, officials said. The United Nations reported that the number of Ukrainian civilian casualties in the more than three-year war has surged in recent weeks amid Washington’s attempts to broker a peace agreement.

Russian President Vladimir Putin backs calls for a ceasefire before peace negotiations, “but before it’s done, it’s necessary to answer a few questions and sort out a few nuances,” Kremlin spokesman Dmitry Peskov said. Putin also is ready for direct talks with Ukraine without preconditions to seek a peace deal, he added.

“We realize that Washington wants to achieve quick progress, but we hope for understanding that the Ukrainian crisis settlement is far too complex to be done quickly,” Peskov said. “There are many details and an array of small nuances that need to be solved before a settlement.”

U.S. President Donald Trump has previously expressed frustration over the slow pace of progress in negotiations aimed at stopping the war, which he said he could end in the first 24 hours of his new administration in January. Western European leaders have accused Putin of stalling while his forces seek to grab more Ukrainian land. Russia has captured nearly a fifth of Ukraine’s territory since Moscow’s forces launched a full-scale invasion on Feb. 24, 2022.

Trump has chided Ukrainian President Volodymyr Zelenskyy for steps that he said were “prolonging” the “killing field,” and the U.S. leader has rebuked Putin for complicating negotiations with “very bad timing” in launching deadly strikes that battered the Ukrainian capital, Kyiv.

Trump has long dismissed the war as a waste of American taxpayer money and of lives lost in the conflict. Senior U.S. officials have warned that the administration could abandon the peace efforts, if it sees no solution. That could spell an end to crucial military help for Ukraine and heavier economic sanctions on Russia.

The U.S. State Department on Tuesday tried again to push both sides to move more quickly.

“We are now at a time where concrete proposals need to be delivered by the two parties on how to end this conflict,” department spokeswoman Tammy Bruce quoted U.S. Secretary of State Marco Rubio as telling her.

“How we proceed from here is a decision that belongs now to the president,” she told reporters, relating a conversation that she had with Rubio. “If there is not progress, we will step back as mediators in this process.”

Russia has effectively rejected a U.S. proposal for an immediate and full 30-day ceasefire, making it conditional on a halt to Ukraine’s mobilization effort and Western arms supplies to Kyiv.

Russian Foreign Minister Sergey Lavrov claimed Wednesday that Ukraine had accepted an unconditional truce only because it was being pushed back on the battlefield, where the bigger Russian forces have the upper hand.

“In the context of the developments on the ground, along the front line where the Kyiv regime is increasingly in retreat, they have made an about-turn and started demanding an immediate ceasefire without any preconditions,” Lavrov said at a briefing in Rio de Janeiro where he was attending a ministerial meeting of the BRICS grouping.

He also suggested that Ukraine’s ceasefire promises weren’t credible. Both sides have accused each other of breaking previous truces. Independent verification of the battlefield claims wasn’t possible.

Meanwhile, Ukrainian civilians have been killed or wounded in attacks every day this year, according to a U.N. report presented Tuesday in New York.

The U.N. Human Rights Office said in the report that in the first three months of this year, it had verified 2,641 civilian casualties in Ukraine. That was almost 900 more than during the same period last year.

Also, between April 1-24, civilian casualties in Ukraine were up 46% from the same weeks in 2024, it said.

The Ukrainian air force said that Russia fired 108 Shahed and decoy drones at Ukraine between Tuesday and Wednesday, predominantly at the cities of Dnipro and Kharkiv.