Ukraine and Russia targeted each other with long-range strikes, officials said Monday, amid continuing uncertainty about whether an agreement to stop their more than three-year war is within reach at the start of what America’s top diplomat called a “very critical” week.

North Korea acknowledged for the first time Monday that it had provided troop reinforcements to aid Russia in its war on Ukraine.

North Korea has for the first time confirmed that it sent troops to fight for Russia against Ukraine. In a report on state news agency KCNA, Pyongyang's military claimed its soldiers helped Russian forces "completely liberate" the Kursk border region, according to an order given by leader Kim Jong Un.

North Korea confirmed for the first time on Monday that it has sent troops to fight for Russia in the war with Ukraine under the order of leader Kim Jong-un and made an important contribution to the liberation of Russian territory occupied by Ukraine.