The secretary general of the United Nations said Thursday that its cash supply had been severely depleted because of what he described as delayed contributions by many member states, and he warned the organization’s employees that they must find ways to cut expenses.

“Our cash flow has never been this low so early in the calendar year, and the broader trend is also concerning,” Secretary General António Guterres said in an internal memorandum to employees shared with The New York Times. “We are running out of cash sooner and staying in the red longer.”

According to a tally known as the “honor roll” on the United Nations website, 112 of the organization’s 193 members have paid their annual assessments in full.

The United States, by far the biggest single contributor at 22 percent of the budget, has not yet paid, but diplomats said the Americans typically completed their payments toward the end of the year.