Vice President JD Vance on Wednesday called on Ukraine to accept an American peace proposal that closely mirrors longstanding Russian demands, including a “freeze” of territorial lines in the three-year war, acceptance of the annexation of Crimea by Russia and a prohibition on Ukraine becoming part of the NATO alliance.

It was the first time a U.S. official had publicly laid out a cease-fire deal in such stark terms and the comments appeared designed to increase pressure on Ukraine, which has long refused to accept Russia’s claims on its lands, particularly in Crimea.

Mr. Vance, speaking during a trip to India, said the United States would “walk away” from the peace process if both Ukraine and Russia refused to accept the American terms. But President Volodymyr Zelensky of Ukraine was clearly the target.

“We’ve issued a very explicit proposal to both the Russians and the Ukrainians, and it’s time for them to either say yes or for the United States to walk away from this process,” Mr. Vance told reporters. “The only way to really stop the killing is for the armies to both put down their weapons, to freeze this thing and to get on with the business of actually building a better Russia and a better Ukraine.”