U.S. State Department Spokesperson Tammy Bruce called for "concrete proposals from both sides" in order for Washington to "move forward" in peace negotiations.

"If they speak to each other in Russian, he doesn't know what they are saying," one Western official told NBC News. Michael McFaul, former U.S. ambassador to Russia, called Witkoff's approach "a very bad idea."

Tougher sanctions "should be applied to (Russia's) banking and energy sectors, targeting fossil fuels, oil, and the shadow fleet," the leaders of Ukraine, the U.K., France, Germany, and Poland said in a joint statement.

"Russia is ready for negotiations without any preconditions," Putin claimed in an address marking the end of the three-day Victory Day ceasefire. He invited Ukraine to begin talks in Istanbul on May 15.

The American-made weapons cannot be exported, even by a country that owns them, without approval from the U.S. government.

While serving as a bishop in Peru, Robert Prevost, now Pope Leo XIV, called the full-scale war "a true invasion, imperialist in nature, where Russia seeks to conquer territory for reasons of power."

Speaking to CNN on May 10, Peskov commented on the latest ceasefire proposal from Ukraine and Europe, responding that Russia needs to "think about" it, but is "resistant" to pressure.

Speaking at a press conference in Kyiv on May 10, President Volodymyr Zelensky rebuked the idea of a demilitarized zone in the war and emphasized the importance of first securing a ceasefire.

"We agreed that a full and unconditional ceasefire must begin on Monday, May 12, for at least 30 days. We jointly demand this from Russia, and we know we are supported in this by the United States," Zelensky said.

The announcement follows mounting fears that the two nuclear-armed countries were on the brink of engaging in another full-scale war.

Ukrainian media outlet ZN.UA reported on May 10 that their law enforcement sources confirmed an ongoing probe by the National Anti-Corruption Bureau into suspected embezzlement, money laundering and bribery.

Iran is preparing to send Russia Fath-360 short-range ballistic missile launchers, Reuters reported on May 9, citing Western security and regional officials familiar with the matter.