ReutersUS Vice-President JD Vance has said the war in Ukraine is "not going to end any time soon", in an interview with Fox News.
Vance said the question facing the US administration now was how it could help Russia and Ukraine "find middle ground" to end the conflict that has been raging for more than three years.
But, Vance added, "it's going to be up to [Russia and Ukraine] to come to an agreement and stop this brutal, brutal conflict".
His comments came shortly after Washington signed a deal with Kyiv to share the profits of Ukraine's rare earth minerals in return for future US security assistance.
Vance made the comments in a wide-ranging interview, in which he defended Trump's approach to the war in Ukraine.
"Yes, of course, [the Ukrainians] are angry that they were invaded," he said. "But are we going to continue to lose thousands and thousands of soldiers over a few miles of territory this or that way?"
Trump suggested this week that Ukraine might be willing to cede Crimea - which Russia invaded in 2014 - in order to reach a truce settlement.
But Ukraine's President Volodymyr Zelensky had earlier implied that he would be unable to accept Russian control of the peninsula, citing the Ukrainian constitution.
In a separate interview with Fox News on Thursday, US Secretary of State Marco Rubio said there needed to be a "breakthrough" in the conflict soon, otherwise Trump "will have to decide how much time to dedicate to this".
Russian President Vladimir Putin this week announced a temporary three-day ceasefire from 8 May, to coincide with anniversary celebrations marking the end of World War Two.
Ukraine's foreign minister, Andrii Sybiha, called for an immediate 30-day ceasefire in response.
But fighting between the two countries has continued.
On Thursday night, a Russian drone attack on Ukraine's south-eastern city of Zaporizhzhia injured 14 people, but caused no deaths.
Separately, Moscow accused Ukraine of using drones to target a market in Russia-controlled southern Ukraine, also on Thursday. Seven were killed and more than 20 were injured, according to Russian officials.
Kyiv denied the accusations, adding that the attack was only targeted at military personnel.
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