The publication of the detailed analysis was a sign that a cease-fire has gone from a theoretical exercise to an urgent and practical issue.
President Donald Trump threatened to put sanctions on Russia after it bombarded Ukraine with missiles, following a U.S. halt on military assistance.
Russia attacked Ukrainian energy facilities with dozens of missiles and drones during the night, officials said Friday, hobbling the country’s ability to deliver heat and light to its citizens and to power weapons factories vital to its defenses.
Russia has retaken about two-thirds of the territory Ukraine seized last summer in the Kursk region of Russia, but at a fearful cost in lives.