Donald Trump's special envoy Steve Witkoff and top diplomat Marco Rubio will hold talks with European counterparts in Paris later on Thursday to discuss efforts to end the war in Ukraine.
Ukraine's foreign minister and defence minister have arrived in the French capital to take part in the discussions.
The talks, which UK Foreign Secretary David Lammy will also attend, form the highest level of transatlantic engagement about the war since February.
European diplomats have said they will urge the US to put more pressure on Russia to agree an unconditional ceasefire.
"We want the US to use a bit more stick," one official said.
Witkoff and Rubio will see French President Emmanuel Macron and his team, before the US Secretary of State holds talks with Lammy and his French and German counterparts. European national security advisers will be involved as well.
The US State Department said the focus would be on how to end the fighting in Ukraine, and that Witkoff would report on his meeting with Russian President Vladimir Putin last week.
Ukrainian President Volodymyr Zelensky's chief of staff Andriy Yermak said "we are working on important issues for the security of Ukraine and the whole of Europe".
Ongoing efforts to secure a ceasefire come days after a Russian missile attack killed at least 35 people and injured 117 in the Ukrainian city of Sumy.
Earlier this month, at least 18 people died in a strike on a residential area in Kryvyi Rih.
In May 2023, prior to returning to the White House, Donald Trump said he would be able to settle the war between Russia and Ukraine "in 24 hours".
His administration has taken action to drastically improve relations with Moscow, while seeking to broker a ceasefire between Russia and Ukraine.
However, it has also held negotiations with Moscow that have cut out Kyiv.
Tensions between Trump and Zelensky have been high since a heated confrontation at the White House in February, where the US leader chided Ukraine's president for not starting peace talks with Russia earlier.
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