WASHINGTON (Reuters) - U.S. President Barack Obama honored a group of women on 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.

The United States wants Mugabe to halt political arrests and media censorship and to honor a power-sharing agreement signed in September 2008 with his political rival, Morgan Tsvangirai.

Mugabe is a pariah in the West, blamed by critics for plunging his southern African country into poverty through his authoritarian rule and economic mismanagement. He has led Zimbabwe since the country's independence from Britain in 1980.

Mugabe has often blamed Western foes for ruining his country via sanctions, which he says are in retaliation for the seizing of white-owned farms on behalf of landless blacks. Critics say the policy is used as a tool to intimidate political opponents and to give land to Mugabe's ZANU-PF party loyalists.

After long negotiations, ZANU-PF formed a unity government in February with the opposition Movement for Democratic Change, led by Tsvangirai, who is now Zimbabwe's prime minister.