Ukrainian President Volodymyr Zelenskyy said he is open to meeting Russian President Vladimir Putin, but only after allies agree on security guarantees to prevent future attacks once the war ends.

In comments released Thursday, he also warned both sides were preparing for further fighting, with Russia building up troops on the southern front line and Ukraine test-launching a new long-range cruise missile.

U.S. President Donald Trump is seeking to end Russia's three-and-a-half-year invasion of Ukraine with a flurry of talks with Zelenskyy and Putin, upending a yearslong Western policy of isolating the Russian leader.

"We want to have an understanding of the security guarantees architecture within seven to 10 days," Zelenskyy said, in comments to reporters released for publication Thursday.

"We need to understand which country will be ready to do what at each specific moment," he said. A group of allies led by Britain and France are putting together a military coalition to support the guarantees.