New Delhi, Dec. 3 -- Diplomats face an uphill battle to reconcile Russian and Ukrainian "red lines" as a renewed U.S.-led push to end the war gathers steam, with Ukrainian officials attending talks in the U.S. over the weekend and Washington officials expected in Moscow early this week.

U.S. President Donald Trump's peace plan became public last month, sparking alarm that it was too favorable to Moscow. It was revised following talks in Geneva between the U.S. and Ukraine a week ago.

Ukraine's President Volodymyr Zelenskyy has said the revised plan could be "workable." Russian President Vladimir Putin called it a possible "basis" for a future peace agreement. Trump said Sunday "there's a good chance we can make a deal."

Still, official...