DAMASCUS, Syria » Some 5 million Syrians are now refugees in their own country, many living hand-to-mouth in vacant buildings, schools, mosques, parks and the cramped homes of relatives. Others are trapped in neighborhoods isolated by military blockades, beyond the reach of aid groups. Already desperately short of food and medicine as winter closes in, they could begin to succumb in greater numbers to hunger and exposure, aid workers say.

The long civil war has forced 2 million Syrians outside the country’s borders, but more than twice that number face mounting privations at home, and the toll keeps rising.

The deepening humanitarian crisis threatens to set the country’s development back decades and dwarfs any aid effort that could conceivably be carried out while the conflict continues, aid workers and analysts say.

The cost of replacing damaged homes and infrastructure alone is estimated at more than $30 billion, and the ruin mounts daily. More than half of the country’s hospitals are destroyed or closed, and according to Save the Children a fifth of Syrian families go without food one week a month. Syria’s economy has shrunk by half.

Even in relatively safe areas, a closer look at bustling streets reveals the displaced spilling from every corner. Thousands of people live in the gyms and hallways of a sports complex turned state-run shelter in the coastal city of Latakia. In the capital, Damascus, newcomers crowd ramshackle hotels, half-finished buildings, offices and storefronts. Long lines form outside the shrinking number of government bakeries still operating. In some of the suburbs, people have confessed to eating dogs and cats, and imams have even issued decrees saying it is religiously permissible.

Outside the Umayyad Mosque in the heart of old Damascus, Nasreen, 25, cradled her baby in her lap one recent evening. She and her siblings, husband and parents, who declined to give their family name for fear of reprisals, were cramped into a single room nearby, having fled the suburb of Daraya after their home was damaged.

With rising rent depleting their savings, and the shop they relied on for income sealed off behind a government blockade, they accept occasional handouts from neighborhood organizations. But what weighs on them most are thoughts of the future: They said they could not imagine when or how they might return to a hometown where entire blocks have been bombed to rubble.

"We have only God," she said.

Even those still in their homes are increasingly suffering as inflation soars and food shortages grow, especially in areas blockaded by the government or rebels. Many are angry and mystified that more help has not reached them from the outside world.

"It is as if we are living on Jupiter or Mars," said Qusai Zakarya, a spokesman for an opposition council in Moadhamiya, south of Damascus, where the government has not allowed aid convoys to enter for nine months. "Everyone is looking at us from the window and we are in a separate world. Everyone left us alone, every single person on this planet."

In a news conference in Kuwait on Thursday, the foreign minister of Turkey, Ahmet Davutoglu, said Turkey, which has absorbed 600,000 Syrian refugees, would keep its border with Syria open, but also expressed his "deep disappointment and frustration because of the absence of a proper reaction by the international community" to the humanitarian crisis.

A $1.5 billion international aid effort, carried out under dangerous and politically charged conditions by the United Nations, the Syrian Arab Red Crescent and smaller local organizations, provides stopgap food, schooling and medicine to millions of people. But it is underfinanced, covers just a fraction of the needs, fails to reach people in blockaded areas and does not begin to address the collapse of Syria’s health, education and economic infrastructure and its devastating implications for the country’s future, aid officials in Syria and across the region say.

"If we continue to deal with this crisis as a short-term disaster instead of a long-term effort, the region will face even more severe consequences," Neal Keny-Guyer, chief executive officer of Mercy Corps, wrote recently, calling for increased U.S. financing and a new focus on longer-term development projects, like repairing water infrastructure.

Some go further, saying the only meaningful humanitarian action now is to end the fighting.

Omar Abdelaziz al-Hallaj, an independent Syrian adviser to aid, development and conflict resolution efforts in the region, told the Lebanese Economic Association in Beirut recently that the focus must be shifted "from saving a few lives to saving more lives by halting the violence."

The war, al-Hallaj and U.N. officials in Syria said, is disintegrating administrative and social structures at a pace that makes it impossible to deliver adequate aid even if financing were available, which it is not. "No donor funds have ever been known to be given in the magnitude of aid needed in Syria," al-Hallaj said.

To help the more than 6 million people displaced or severely affected by the crisis inside Syria, the United Nations has asked for $1.5 billion, far less than the $3 billion it has requested to aid the 2 million refugees outside the country. The discrepancy stems in part from U.N. principles of dealing with sovereign states, under which the plan is designed only to support efforts led by the Syrian government. That creates a politically awkward situation, in that much of the need is in rebel-held areas.

If the war goes on for another year, al-Hallaj said, Syria "will be reduced to the bottom of the development ladder, along with countries like Somalia and Yemen," a shocking fall for a country that before the war produced most of its own food and medicine, and despite worsening economic inequality had a strong social safety net and educational system by regional standards.

The Syrian government prides itself on continuing to pay salaries even in areas controlled by the opposition, and in some cities local ministry offices continue to work with U.N. agencies. But the estimated $10 billion the government used to pump annually into local spending for social services, utilities, subsidies and the like has mostly evaporated, al-Hallaj said.

Aid workers and analysts warn that as the war continues into its third winter — with harvests depleted by fighting — deaths from hunger, disease and cold could begin to exceed those from the violence, which has killed 115,000 people. A trickle of reported malnutrition deaths of sick and vulnerable people in blockaded areas could be a harbinger of more widespread famine, aid workers say.

In Damascus recently, where most U.N. agencies work in the otherwise nearly empty Four Seasons Hotel, aid workers offered example after example of how their sizable efforts remain a drop in the bucket.

Barbara Atherly, head of UNICEF’s education program in Syria, said the agency was providing 1 million children with schooling, increasingly by distributing educational materials to families and communities to organize lessons themselves, since many schools have been destroyed and teachers have dispersed.

But more than 3 million children are directly affected by the crisis, UNICEF’s Syria director, Youssouf Abdel-Jelil, said, including more than 2 million internally displaced and another million in hard-to-reach conflict areas. That does not include more than 1 million children who have fled the country.

Overall, 2 million children have not had regular access to schooling in the past year, he said, adding that as the conflict continues, "there is a real risk of a lost generation of Syrians."

The World Food Program is feeding 3 million people a month, plying dangerous roads with 1,200 trucks and employing 9,000 people. But that leaves 2 million displaced people without food aid, and understates the need in pockets where deliveries have not reached in months.

Those areas include rebel-held suburbs of Damascus blockaded by the government and government-held parts of Aleppo.

"Their situation is dire," said Matthew Hollingworth, the food program’s Syria director. He said hundreds of thousands of people are living on what food they can grow and the small amounts of food they can get past checkpoints, as stored food stocks dwindle "to a frighteningly low level."

Tarik Jasarevic, a spokesman for the World Health Organization, said replacing the prescription drugs once provided by the government would cost $500 million yearly, dwarfing his agency’s entire budget in Syria.

In the southern province of Daraa, a third of health workers have fled, especially from rural areas, Abdel-Jelil of UNICEF said. He described one woman who crossed the front lines to bring her children to the city for vaccines.

Most of all, he said, children are paying the price in terms of health, education and psychological trauma.

"A lot are talking adult talk, about visas, about borders, about relatives who are outside of the country," Abdel-Jelil said. "They still have dignity and resilience. But there is a limit to resilience."

© 2013 The New York Times Company