The United Nations' secretary general sent out a letter warning that it could run out of funds in a matter of weeks.

Secretary General António Guterres said in a Monday letter to 37,000 employees at the U.N. secretariat that the U.N. is running a $230 million deficit and could run out of money by the end of October, according to CBS News.

“Member States have paid only 70 percent of the total amount needed for our regular budget operations in 2019. This translates into a cash shortage of $230 million at the end of September. We run the risk of depleting our backup liquidity reserves by the end of the month,” Guterres, 70, said.

He added that “additional stop-gap measures” would be taken to maintain salaries and entitlements amid the deficit but did not specify what those measures would be. In the letter, Guterres touched on restricting official travel, reducing services, and postponing conferences.

Out of the 193 member states, 129 have paid their annual dues. U.N. spokesman Stéphane Dujarric said at a briefing in New York that the member states who haven’t paid need to do so “urgently and in full.”

“This is the only way to avoid a default that could risk disrupting operations globally,” he said.

The total U.N. operating budget is about $5.4 billion. The United States shoulders the largest burden of that, contributing about 22%.

[ Opinion: The UN secretary-general is begging for cash. He should answer questions first]