World Food Program and Syrian Red Crescent personnel unload humanitarian aid in Damascus. Before the civil war, Syria produced much of its own food, but the fighting has prevented farmers from tending their fields. (Bassam Khabieh/Reuters)

Syria is heading for a record low harvest this year, the United Nations warned Monday, putting the food supply for millions of civilians at risk as drought adds to the misery of the country’s war-weary population.

The organization’s food agency estimates that Syrian wheat production will plummet to a record low after limited rainfall over the winter. Wheat production in the country is expected to reach a maximum of 2 million tons this year, less than half of the 5.1 million tons needed annually, the World Food Program said.

As the crisis looms, the Syrian government said Monday that Iran had stepped in with a delivery of 30,000 tons of food aid — about the same amount that the United Nations delivers in a month. The shipment is part of a wide package of support from the Iranian government, which has propped up its ally in Damascus with weapons and oil through a $3.6 billion credit line.

Although the United Nations attempts to ensure that the delivery of its aid is not politicized, such restrictions are unlikely with Iranian food aid, meaning it could be delivered to Syria’s armed forces.

The delivery comes as the government enters campaign mode, with President Bashar al-Assad expected to run for reelection for a third seven-year term this summer.

The official Syrian Arab News Agency said further shipments would follow “to ensure the flow of goods in the Syrian markets.”

Before the civil war, Syria produced much of its own food, but the fighting has prevented farmers from tending their fields, while prices for fuel and distribution problems also have hampered production.

Some of the regions most affected by violence — Aleppo, Idlib and Hama — also promise to be among the worst hit by drought. The areas of Raqqah, Deir al-Zour and Hasakah also are expected to be severely affected.

With just weeks to go before the end of Syria’s rainy season, rainfall has been less than half the average amount, the World Food Program said. The agency used satellite imagery to examine the effect on the country’s vegetation, saying there were “extensive delays” in crop development.

“It comes in areas that are already suffering hugely,” said Abeer Etfa, a regional spokeswoman for the agency. “It is a very fragile environment, and we have issues of access. This could push more people into hunger. It could push more people out of the country.”

About 6.5 million Syrians have been displaced internally by the war, and more than 2.5 million have fled to neighboring countries — meaning almost half the country’s population has been uprooted.

Humanitarian agencies have been pushing for better cross-border access. U.N. trucks crossed into Syria from Turkey last month for the first time, bringing food, bedding and medicine to the northeastern city of Qamishli.

International agencies also are facing huge funding shortfalls. The United Nations cut its food baskets by a fifth last month. Less than half of the $2.3 billion pledged by the international community in January has materialized.

In 2008, Syria was hit by a severe drought that lasted several years and displaced tens of thousands of people. The misery caused by that drought has been cited by analysts as one of the factors that contributed to Syria’s uprising in 2011.