U.S. President Donald Trump has acknowledged in private that Russia is difficult to negotiate with because they "want the whole thing," referring to Ukraine, the WSJ reported, citing sources familiar with the comments.

The visit marks Merz’s first trip to Ukraine, and the first time all four leaders have travelled there together.

A notice about the airspace closure was published on the U.S. Defense Department's NOTAM (Notice to Airmen) website on May 10, as cited by Ukrainian defense news outlet Militarnyi.

"As in the past, it is now for Russia to show its willingness to achieve peace," the EU's statement reads.

Kremlin spokesperson Dmitry Peskov rejected the idea of a 30-day ceasefire between Russia and Ukraine, claiming in an interview with ABC News on May 10 that it would be "an advantage" for Ukraine.

"Our involvement in the war was justifiable, and this belongs to our sovereign rights," North Korean dictator Kim Jong Un said. "I regard this as part of the sacred mission we must execute for our brothers and comrades-in-arms."

The number includes 1,310 casualties that Russian forces suffered over the past day.

"We have a plan B and a plan C. But our focus is plan A, the essence of which is to get everyone's support" for Ukraine's accession, EU foreign policy chief Kaja Kallas said.

"(T)he presence at the Victory Parade of a country that bombs cities, hospitals, and daycares, and which has caused the deaths and injuries of over a million people over three years, is a shame," Polish Prime Minister Donald Tusk said.

"According to the participants of the performances, their goal is to remind the civilized world of the barbaric actions of Moscow, which for many years and decades has systematically violated international law," a source in Ukraine’s military intelligence agency (HUR) told the Kyiv Independent.

"I have great hope that an agreement for a ceasefire in Ukraine will be reached this weekend," German Chancellor Friedrich Merz said on May 9, shortly before traveling to Kyiv alongside the leaders of France, Poland, and the U.K.

U.K. Prime Minister Keir Starmer, French President Emmanuel Macron, German Chancellor Friedrich Merz, and Polish Prime Minister Donald Tusk will arrive in Kyiv early on May 10.

The United States embassy in Kyiv on May 9 issued a warning that Russia could launch "a potentially significant" attack in the coming days, despite Putin's self-declared Victory Day "truce."