International donors meeting in Oslo, Norway have pledged about four-point-five billion dollars in aid to rebuild southern Sudan after 21 years of civil war.

The United States pledged $1.7 billion over the next two years. However, U.S. Deputy Secretary of State Robert Zoellick said Tuesday the aid is dependent on Sudan ending a separate conflict in its western Darfur region. He said the violence in Darfur casts a dangerous shadow over all of Sudan.

The United Nations estimates that the fighting in Darfur between pro-government Arab militias and rebels has left 180,000 people dead and more than two million others displaced.

Those aid donations made in Oslo Tuesday and Monday will go to help humanitarian and rebuilding efforts in southern Sudan, following a peace deal between the government and southern rebels earlier this year.