KAMPALA, Uganda — South Sudan’s civil war presents humanitarian workers with “one of the unique crises” in the world, the president of the International Committee of the Red Cross said Monday.

“This is not a crisis which can be reduced to the conflict,” Peter Maurer told reporters in Uganda’s capital, Kampala. “This is also a crisis where the uncomfortable elements of poverty, of lack of development, of international pressures on the economy, pay an enormous toll.”

He described “a special crisis” in which even ICRC’s relief operations have had to be moved several times over the last three years in order to keep up with people fleeing violence. He said it was hard to move hospitals and other infrastructure to service a moving population.

Maurer said South Sudan’s “economic fragility, the inability of the state to pay salaries, has had so much impact” on the conflict, which started in December 2013 and has often been fought along ethnic lines.

Maurer visited parts of South Sudan and later toured some refugee camps in neighboring Uganda, which is struggling to keep up with over 1 million refugees from South Sudan.

An average of 1,800 South Sudanese have been arriving daily in Uganda over the past 12 months, according to the United Nations refugee agency. Another 1 million or more South Sudanese are sheltering in Sudan, Ethiopia, Kenya, Congo and Central African Republic. Most of the refugees are women and children.

Both sides have committed serious rights violations, including murder and rape, against civilians, according to U.N. investigators. Armed groups, including government troops, have sometimes been accused of preventing aid workers from reaching people in need of help.

Maurer urged both sides in South Sudan’s conflict to respect international humanitarian law.

“We may be some time away from a political solution to the conflict in South Sudan, but we should be no time away from the respect of international humanitarian law during conflict,” he said.