AU leaders say the "very serious and dangerous situation" should be resolved via "political negotiations" overseen by the United Nations.
The African Union on Thursday condemned Russia's attack on Ukraine and called for an "immediate ceasefire", saying the situation risked escalating into "a planetary conflict".
The bloc's current chair, Senegalese President Macky Sall, and Moussa Faki Mahamat, chair of the African Union Commission, said in a joint statement they were "extremely concerned" by the invasion.
They called on Russia to "respect international law, the territorial integrity and national sovereignty of Ukraine".
Russia launched a full-scale invasion of Ukraine on Thursday, killing dozens as airstrikes hit military installations and ground forces moved in from the north, south and east.
The AU leaders said the "very serious and dangerous situation" should be resolved via "political negotiations" overseen by the United Nations.
Across Ukraine, at least 68 people were killed Thursday, including soldiers and civilians, according to an AFP tally from Ukrainian official sources.