The United States promised more military support for Ukraine, including drones, and is doing preliminary work on whether to send fighter aircraft, as fighting raged on in the east of the country five months into Russia's invasion.
Moscow and Kyiv signed a landmark deal on Friday to unblock grain exports from Black Sea ports. However, representatives declined to sit at the same table and avoided shaking hands at the agreement ceremony in Istanbul, reflecting wider enmity.
Ukrainian President Volodymyr Zelensky hailed Friday's agreement as unlocking around $10 billion worth of grain exports, needed to ease a food crisis.
But on the war, he said there could be no ceasefire unless lost territory was retaken.