KHARTOUM, Sudan -- The top UN humanitarian official says Sudan has a historic opportunity to overcome years of bloody conflict and instability, but needs urgent international assistance.

Mark Lowcock, the UN under-secretary general and emergency relief co-ordinator, spoke during his first visit to Sudan since a joint military-civilian government was formed. It replaced former President Omar al-Bashir, who was ousted by the military in April amid mass protests.

Lowcock told The Associated Press on Saturday he's "hopeful that further progress can be made on peace" with rebels in the country's restive southern provinces, where fighting has displaced 1.9 million people.

But he warned that Sudan faces stiff challenges, including economic collapse, malnutrition and disease.

He appealed to the international community to "provide more help faster" to support the new government's efforts to rebuild.