UNITED NATIONS (AP) — A funding shortage has cut off aid to 4 million Yemenis and experts are increasingly worried that “the window to prevent famine” in the war-torn country is closing quickly, the U.N. humanitarian chief said Thursday.

Mark Lowcock told the U.N. Security Council that aid agencies are only reaching 9 million people a month, down from more than 13 million at the beginning of the year.

“What is to be the fate of the 4 million we no longer have the money to help?” he asked.

On Sept. 15, Lowcock for the first time singled out Saudi Arabia, the United Arab Emirates and Kuwait for giving nothing to this year’s $ 3.4 billion humanitarian appeal for Yemen, the Arab world’s poorest country which has been engulfed in conflict since 2015.

Days later, Kuwait announced a $20 million donation and Saudi Arabia publicly committed to providing $204 million to U.N. aid agencies, part of its $500 million pledged in June. That pledge was half of its 2019 commitment. The UAE, which had been a top donor, did not announce any funding for this year.

Lowcock said new funding increased donations to the U.N. appeal from 30 percent last month to 42 percent this month which is welcome, but last year at this time it was 65 percent funded, and the shortage “still mean that more key programs are at risk of shutting down.”

Yemen’s conflict started with Houthi Shiite rebels backed by Iran capturing the capital, Sanaa, in 2014, forcing the internationally recognized government to flee. The following year, a Saudi-led coalition backing the government intervened to battle the rebels and curb Iran’s influence in what has turned into a stalemated regional proxy war. Since then, more than 100,000 people — fighters and civilians — have been killed.

Lowcock told the Security Council that famine was averted two years ago when action was taken on five priority issues: protecting civilians, access for humanitarian workers, funding, the economy and progress toward peace.

In the last month, he said, the conflict has escalated and “there are now 47 active front lines across Yemen — the most every recorded.”

Civilian casualties reached their highest level this year in September, with the heaviest clashes in Hodeida, Marib and Al Jawf, causing tens of thousands of people to flee their homes.

“In recent days, hostilities have subsided somewhat, but it is not enough,” he said, warning that a major confrontation in Marib city “could be disastrous,” and anything jeopardizing the smooth operation of the country’s major port at Hodeida, which is a lifeline for aid deliveries, “would put millions of lives at risk.”

As for delivering aid, Lowcock said front-line humanitarian staff face challenges in the government-controlled south “due to insecurity, including harassment by armed groups.” In the Houthi-controlled north, he said, “agencies are grappling with more severe access challenges, mainly the result of challenges” imposed by the rebel group.

With the window to prevent famine closing, he urged countries that made pledges to the U.N. humanitarian appeal to deliver the money and to increase their support.

Lowcock said Yemen’s economy needs regular foreign exchange injections to subsidize commercial imports, pay salaries and help stabilize the local currency, the rial, which traded at an all-time low of 850 rials to the dollar in the south in September.

“This worked in the past and it can work again,” he said. “The economic support we saw in 2018 was critical to the famine prevention effort.”

While food imports have remained stable, Lowcock said, the cost of food and other basic goods is out of reach for millions of families and there are major fuel shortages in the north. He said the government is blocking the entry of 20 commercial ships with fuel waiting to enter the port of Hodeida due to an ongoing dispute with the Houthis over management of import revenues, clearing only several this month on an exceptional basis.

“I am not convinced that humanitarian agencies — even were they to have more funding — can prevent famine if there is no accompanying support for the economy,” Lowcock said. “The crisis in Yemen urgently needs a political solution. That would help move the country back from the edge of famine.”