ERBIL, Iraq — Word of the Islamabad ceasefire reached the Baharka displacement site outside this northern Iraqi city within minutes of the joint statement Sunday afternoon, carried on the cracked screens of shared phones and then, more slowly, on the camp loudspeaker that ordinarily called the evening meal. Within an hour, families who had been on the move for six weeks were doing two things at once: weeping with relief, and asking whether they could now go home.

The answer, aid workers across the region said, was almost universally no — at least not yet, and not safely. The Islamabad joint statement announcing a halt to hostilities effective Wednesday at midnight GMT was met across a humanitarian footprint stretching from western Iraq to Yemen’s Hodeidah governorate with what United Nations and nongovernmental staff described as cautious relief shadowed by the knowledge that a ceasefire on paper is not yet a corridor on the ground.

“There is a moment of stunned quiet in these places when the news comes,” said Caroline Holt, the International Federation of Red Cross and Red Crescent Societies’ director of disaster, climate and crises, speaking by phone from Geneva. “And then there is a wave of questions that we cannot answer yet. When can we go back. Is the road clear. Is my house there. Is my school there. Is my brother there. We are working as fast as we can to be able to answer even one of those questions truthfully.”

The Office for the Coordination of Humanitarian Affairs put the total displaced population across Iran, Iraq, Lebanon, Syria and Yemen as a result of the war at 4.16 million as of Saturday, a figure that does not include the roughly 280,000 Iranian nationals who have crossed into eastern Turkey or the smaller flows into Armenia and Azerbaijan. About 1.78 million of those displaced are in Iraq, predominantly from Anbar and the Tigris valley around the Ain al-Asad and Erbil air bases; an estimated 760,000 are internally displaced inside Iran, mostly from the industrial belts around Bandar Abbas, Isfahan and Tabriz; and roughly 612,000 Lebanese have moved north from the south and the Bekaa.

OCHA officials said in a statement Sunday evening that they were preparing a 72-hour humanitarian assessment to begin the moment the ceasefire took effect Wednesday, with priority given to unexploded-ordnance surveys along return corridors, the restoration of water and electricity in heavily damaged urban districts, and the reopening of primary health-care clinics. The agency’s regional humanitarian coordinator, Ramesh Rajasingham, said in the statement that the immediate post-ceasefire phase would be “the most operationally fragile, and the most consequential, of the entire response.”

At Baharka, where the population has grown from a steady-state of about 2,400 to more than 9,000 since mid-March, families spent Sunday afternoon clustered around the camp’s tea stall and around a battered television in the management office showing Al Jazeera Arabic. Layla Hassan, a Beirut-based regional analyst who had traveled to Erbil with a small delegation from the Issam Fares Institute, said the mood in the camp was unlike any she had observed during the war’s earlier weeks.

“It is not joy. It is something more careful than joy,” Hassan said in an interview at the camp’s edge. “These are families who have been displaced before — many of them twice, some of them three times. They know what a ceasefire is, and they know what a ceasefire is not. They are asking each other, in Arabic and in Kurdish, whether to start packing. And the older women are telling them to wait.”

Among those waiting was Nidal al-Dulaimi, a 47-year-old former municipal clerk from Hit, in Anbar, who arrived at Baharka with his wife, four children and his mother on March 21 after a U.S. counter-battery strike landed within 800 meters of their street. He said he had heard the ceasefire news from his oldest son, who had been watching a video on a borrowed phone.

“I told him to be quiet, because I did not want my mother to hear it and start packing the small bag she has been packing every night since we left,” al-Dulaimi said, smiling for the first time in what he said had been three weeks. “She is 79. She does not have another move in her. I want to be sure before I tell her.”

In Lebanon, where reception schools in Beirut’s Achrafieh district and across the Mount Lebanon governorate have been running on four-shift rotations to accommodate Lebanese displaced from the south alongside Syrian and Palestinian refugee children, UNICEF country representative Edouard Beigbeder said the ceasefire news had produced an immediate logistical question: whether to keep accelerated learning programs running through the summer or to plan for a phased return to home schools in the south beginning in late May.

“We are not going to make that decision today,” Beigbeder said by phone from Beirut. “We are going to make it after the first week of the ceasefire holds, after the unexploded-ordnance teams have walked the schoolyards in Tyre and Nabatieh, and after the children themselves tell us whether they feel safe to go.”

The Iranian humanitarian picture remained the most opaque. International aid agencies have had limited access to internally displaced populations inside Iran throughout the war, and what assessments exist have relied heavily on Iranian Red Crescent Society reporting and on a small number of WHO field staff. A WHO situation update circulated to donor governments Sunday and obtained by MetaCurrents estimated that hospital capacity in Isfahan and Tabriz remained below 40 percent of pre-war function, and that fuel rationing for ambulances had become the binding constraint on emergency response in several mid-sized cities.

“A ceasefire does not refill an oxygen cylinder,” said Soroush Mehrian, an Iranian-Canadian public-health researcher at the University of Toronto who has been collecting reports from physicians inside Iran through a diaspora network. “The work that has to happen inside Iran in the next 30 days is enormous, and it has to happen on infrastructure that has been depleted for six weeks. Goodwill does not substitute for diesel.”

In Yemen, where Houthi cross-border launches and Saudi-led intercepts have continued through the weekend, aid coordinators in Sanaa and Aden said the Islamabad statement’s reference to “associated regional fronts” had been read with particular care. Wassim Mushantaf, a senior protection officer with the Norwegian Refugee Council in Aden, said his team was preparing for the possibility that the cessation of hostilities would not initially extend to all Houthi operations, and that displacement flows out of Hodeidah and Saada governorates could continue into next week even as families elsewhere began to return.

“We are planning for two scenarios at once,” Mushantaf said. “We are planning for a Yemen that gets quieter on Wednesday, and a Yemen that does not. The families we serve have asked us to plan for both, and not to promise them either.”

UN officials said the secretary-general would convene a closed-door donor coordination call Monday evening to align reconstruction and return planning with the ceasefire timeline, and that a revised consolidated humanitarian appeal would be issued before the end of the week.