Norway's foreign minister says South Sudan's leaders have inflicted a massive humanitarian crisis on the population threatened by a famine, adding that a stop in fighting in the civil war is needed urgently.

Borge Brende says South Sudan is "one of the world's biggest humanitarian disasters," affecting nearly 6 million people. He said the crisis is man-made and a solution must include agreement with opposition groups.

Brende called Tuesday for a worldwide ban to stop "the flow of weapons" into the world's newest nation.

According to UNICEF, more than 5 million people in South Sudan don't have access to safe, clean water, compounding the country's problems of famine and civil war. Since 2013, South Sudan has been embroiled in a civil war that has killed at least 50,000 people.