Ukraine said its top objective at the first face-to-face talks with Russia in over two weeks, due to take place in Turkey on Tuesday, is to secure a ceasefire, although both it and the United States were skeptical of a major breakthrough.

The more than month-long invasion, the biggest attack on a European nation since World War Two, has seen over 3.8 million people flee abroad, left thousands dead or injured, and has brought isolation to Russia's economy and tumult to markets...