Officials in Sudan’s White Nile state said they have received nearly 45,000 South Sudanese refugees in the last two days as fighting continues in parts of South Sudan’s neighboring Upper Nile state.

Al Tayib Mohamed Abdullah, the head of the refugee’s coordinating committee, said three new sites have been identified in the Jebelain and El Salam localities to accommodate the new arrivals. Still, he expressed concern that crowded conditions and poor water and sanitation systems might spread disease.

Abdhullah called on the United Nations High Commissioner for Refugees to expedite the delivery of humanitarian aid to assist the new arrivals. He said there was also a need among an unknown number of people who are still at the border between the two countries.