Secretary-General Antonio Guterres warned that the U.N. is facing its "worst cash crisis" in nearly a decade because 64 of its 193 members have not paid their annual dues, including the U.S., its largest contributor.

U.N. spokesman Stephane Dujarric said the secretary-general has written to all members saying "the organization runs the risk of depleting its liquidity reserves by the end of the month and defaulting on payments to staff and vendors." By the end of September, Dujarric said, member states had paid only 70% of the total assessment for the regular budget, compared with 78% at the same time last year.

According to the U.N., 129 countries had paid $1.99 billion in dues for the U.N.'S 2019 operating budget by Tuesday. It said $1.386 billion is owed for this year. In addition to the U.S., other countries that haven't paid their dues are Brazil, Iran, Israel, Mexico, South Korea, Saudi Arabia and Uruguay.

Dujarric said measures the U.N. Secretariat put in place early in the year to align expenditures with cash inflows have averted "major disruptions" but "are no longer enough." Since the U.N. Secretariat could face a default in salaries and payments by the end of November, Dujarric said the secretary-general has requested immediate steps including further reductions in official travel and postponing spending for goods and services. The secretary-general stressed that cash flow is a recurrent problem and the U.N. is now driven to prioritize work based on cash availability, thus undermining its mandates and obligations "to the people we serve," Dujarric said.