U.S. President Barack Obama honored a group of women Monday who have confronted Zimbabwean President Robert Mugabe and said they had defied a dictator.

"They often don't get far before being confronted by President Mugabe's riot police," Obama said at a ceremony for Magodonga Mahlangu and the organization she helps lead -- WOZA, which stands for Women of Zimbabwe Arise.

"By her example, Magodonga has shown the women of WOZA and the people of Zimbabwe that they can undermine their oppressors' power with their own power -- that they can sap a dictator's strength with their own," he said, presenting the annual Robert F. Kennedy Human Rights Award.