WASHINGTON—Ukraine’s weekend attacks against military airfields deep inside Russia signal the long-stalemated war is entering a perilous phase, with both sides seemingly intent on escalation and prospects for a U.

President Volodymyr Zelenskyy said Defense Minister Rustem Umerov would sit down with Russian officials at the second round of peace talks on Monday.

Delegations from Ukraine and Russia held their second set of direct peace talks in less than a month, but they didn't make any major progress toward ending the three-year-long conflict. FOX's Mike Emanuel reports.