Ukraine's President Volodymyr Zelensky said Monday his country would respond if Russia did not agree to the "energy ceasefire" announced by US President Donald Trump.
The Kremlin refused to say if an energy target truce was in place. Ukraine said that Russia struck its power plants and gas facilities after Trump posted on social media that a deal had been reached.
"If Russia does not agree to an energy ceasefire, we will respond," Zelensky told the Warsaw Security Forum via videolink on Monday.
Trump sowed confusion when he said there was an agreement between Russia and Ukraine without providing details, sparking astonishment in Kyiv, silence from Moscow. Ukraine's Western allies have supported Zelensky.
Trump's administration has pushed to end Europe's deadliest conflict since World War II -- now in its fifth year -- but diplomacy has so far failed to end fighting.
With gas prices surging ahead of US midterm elections, Trump has turned to major oil producer Russia as a possible source of relief, unilaterally announcing the halt on strikes after easing sanctions on Moscow to enable diesel exports.
"We are waiting for the details of the conversation between the Americans and the Russians, and we are waiting to see what specific steps the Americans are ready to take," Zelensky said.
Zelensky added that any ceasefire must apply on the ground and not just on social media.
"An energy ceasefire and other steps to reduce escalation and guarantee security are truly needed here in reality, not just on Truth Social," Zelensky said.
The Kremlin on Monday refused to say if it had agreed to an energy ceasefire.
"Contacts are continuing. As soon as we have anything to say on this matter, we will be sure to let you know," Kremlin spokesman Dmitry Peskov told reporters, including AFP.
Moscow also rejected Kyiv's call for a separate 60-day complete ceasefire to enable it to hold elections, following Trump's surprise weekend remarks over the weekend urging Ukraine to stage a nationwide presidential vote.
"We don't want a ceasefire, we want long-term peace," Peskov said. "I do not think he deserves a respite," Foreign Minister Sergei Lavrov added.
Russia's President Vladimir Putin has repeatedly said Moscow intends to seize the rest of east Ukraine by force and has rejected face-to-face talks with Zelensky.
In recent weeks, Russia has increased strikes on Ukraine -- especially on its capital Kyiv -- as Ukrainians brace for another winter of war.
Trump's announcement came two days after he declared an easing of US sanctions on Russian diesel, infuriating Ukraine and its European allies.
European leaders had welcomed Trump's ceasefire call on Sunday, but many were cautious.
"Russia is not interested in a ceasefire, or in de-escalation or peace. It is interested only in domination," Poland's prime minister Donald Tusk told the Warsaw Security Forum.
He added that "this was the moment" when Europe and the United States should stand together on Russia, saying that "Ukraine is fighting for survival, while Russia is fighting for dominance."
Many in Europe were waiting for Washington to provide more details.
In Paris, President Emmanuel Macron said Monday appeared wary.
There can only be progress "if there is a real truce on both sides," Macron told reporters, saying "the facts show Russia has continued to bomb energy infrastructure in the last hours".
But he added: "We say 'yes' to seeking an energy ceasefire and resuming peace talks ... but 'no' to giving in to the Russian threat."
Britain's Prime Minister Andy Burnham said Sunday that he backed Trump's call for the ceasefire, but warned that Moscow had intensified strikes on Ukraine's energy infrastructure over the weekend.
"This is an attack on Ukrainian civilians, plunging them into cold and darkness," he said.
Kyiv's European allies have worried that Trump will be too soft on Russia and that Washington will strike a deal on Ukraine over their heads.
Russia's war against Ukraine, which the Kremlin launched in 2022, has killed hundreds of thousands.