As foreign outrage mounts over evidence of possible executions and other atrocities by Russian forces in Ukraine, Germany’s defense minister says Europe must consider stepping up penalties for Moscow by boycotting its gas exports, an economically painful step European leaders previously avoided.

Russian troops left the heavily contaminated Chernobyl nuclear site early Friday after returning control to the Ukrainians, authorities said, as residents in parts of eastern Ukraine braced for renewed attacks and awaited blocked supplies of food and other humanitarian relief.

A delegation of Ukrainian lawmakers visited Washington on Wednesday to push for more U.S. assistance, saying their nation needs more military equipment, more financial help and tougher sanctions against Russia.

Ukrainian President Volodymyr Zelenskyy said there was no reason to believe Russia's announcement that it would reduce military activity near Kyiv, the capital, as well as in the northern city of Chernihiv, given what's happening on the ground.