More than 480,000 people have fled their homes in western Iran and across the porous border into Iraqi Kurdistan since the war’s opening salvos a month ago, the United Nations refugee agency said Tuesday, warning that shelter capacity in three Iranian provinces had been exhausted and that food rations in the largest receiving camps were being cut to keep stocks from running out.

The figures, released by UNHCR’s regional office in Amman, mark the largest single-month displacement event in the Middle East since the 2014 collapse of northern Iraq, agency officials said. The bulk of the movement has come from Khuzestan, Kermanshah and Ilam provinces, where Israeli strikes on petrochemical installations, suspected missile production sites and dual-use rail infrastructure have driven civilians from industrial towns toward the agricultural interior or across the frontier into Sulaymaniyah and Erbil governorates.

“We are now seeing families arriving who left after a second or third strike near their neighborhood, not the first one,” said Mariam Qasemi, a UNHCR field coordinator working out of a transit site near Penjwen. “They waited, they hoped, and then the windows broke a final time.”

Iraq’s federal government, in coordination with the Kurdistan Regional Government, has opened four new transit sites since March 22 and is preparing a fifth near Kalar, according to a statement from the Ministry of Migration and Displaced. Federal officials in Baghdad said roughly 112,000 Iranian nationals had been registered at border crossings, while an unknown additional number had entered through unofficial mountain routes long used for trade. Another 60,000 Iraqis, mostly from Shia shrine cities visited by Iranian pilgrims, have themselves moved south after smaller-scale Israeli strikes on what the Israel Defense Forces described as Iranian-linked logistics nodes in Diyala and Wasit.

Inside Iran, the picture is harder to verify. The Iranian Red Crescent put internal displacement at 368,000 as of Monday, but Western diplomats and aid workers contacted by phone said the true figure was almost certainly higher, citing satellite imagery of emptied residential blocks in Bandar Imam Khomeini and Ahvaz. Iranian state television has shown buses moving civilians inland to Isfahan and Yazd provinces, where local authorities have requisitioned school dormitories and wedding halls.

The humanitarian strain is being compounded by damaged infrastructure. Strikes in the past 10 days on a power substation outside Ahvaz and on a water-pumping complex in Abadan have left intermittent electricity and degraded water service for hundreds of thousands of residents who have not yet fled, said Dr. Hossein Tabrizi, a physician with the Iranian Society of Internal Medicine who has been coordinating relief shipments from Tehran. He said three hospitals in Khuzestan were running diesel generators around the clock and that supplies of insulin and dialysis consumables were thinning.

“This is not a situation where we will see the worst of it on television tomorrow,” Dr. Tabrizi said in a telephone interview. “The worst of it will come in two weeks, when chronic patients stop showing up because they cannot reach us.”

In Yemen, separate UN figures released Tuesday put the number of newly displaced at 71,000 since mid-March, when Houthi forces escalated drone and missile launches at U.S. naval vessels and Gulf shipping and drew retaliatory U.S. and Saudi airstrikes on launch sites around Saada and Hodeidah. Aid workers said displacement in Yemen was layering atop a population already battered by a decade of war and a cholera outbreak that resurfaced in February.

The International Committee of the Red Cross said its delegates had been granted limited access to a detention facility in Khuzestan holding what Iranian authorities described as foreign nationals picked up near a damaged industrial site, though the ICRC declined to provide further details. Separately, U.S. Central Command on Monday confirmed three additional American service members killed in a drone strike on a forward operating base in eastern Syria, bringing the U.S. military death toll since the war’s start to roughly 340.

Donor pledges have so far lagged behind need. UNHCR’s flash appeal for $480 million, issued March 24, was 31 percent funded as of Tuesday, with the largest contributions coming from Germany, Japan, Qatar and the European Commission. U.S. officials said additional emergency funding would be announced in the coming days but did not commit to a figure, and several European diplomats privately expressed concern that Washington’s focus remained on military operations rather than civilian relief.

Saudi Arabia and the United Arab Emirates, both of which have continued to intercept Houthi and Iranian-aligned projectiles over their own territory, have pledged a combined $220 million in cash and in-kind aid routed through the Saudi Red Crescent, according to a joint communique issued in Riyadh. The funds are to be split between Iraqi border governorates and Yemeni internally displaced sites.

The OPEC+ emergency session opening Wednesday in Vienna has drawn the attention of donors and aid agencies alike. A production hike, widely expected, could ease Brent prices and the cost of diesel that fuels the generators, water trucks and refrigerated transport on which the relief operation now depends, said Layla Hassan, a Beirut-based regional analyst.

“Every dollar off the barrel buys you another generator-hour in a clinic in Penjwen,” Hassan said. “That is not abstract right now.”

Aid coordinators said they expected displacement figures to climb further this week as strikes continued and as families who had so far stayed put exhausted savings. UNHCR officials said a revised flash appeal, raising the funding target above $700 million, was being prepared and would be presented to donors in Geneva on Friday.