Robert Zoellick is welcomed by an African Union soldier as he arrives in Northern Darfur region's administrative capital El Fasher

U.S. Deputy Secretary of State Robert Zoellick has called on the Sudanese government to accept responsibility for disarming the Arab militias accused of subjecting civilians to rape and other violence.

Mr. Zoellick arrived in the war-torn Darfur region Friday to assess the security and humanitarian crisis that has left tens of thousands of people dead and has displaced more than two million others.

He is scheduled to meet with Sudanese officials later.

Earlier, the U.S. diplomat met the head of the African Union mission in Sudan Said Djinnit. Both agreed that security remains unacceptably low and that an increase in the number of peacekeepers and an expansion of their presence is essential to restoring civility.

Some information for this report provided by AFP and AP.