The Alaa Aldin family bakery could have been a casualty of Syria’s civil war. Instead, it has become a symbol of what American officials describe as the resilience of refugees trying to survive a conflict that many fear has been forgotten.

The three brothers Ahmad, Iyad and Bassam Alaa Aldin decided to relocate the business in 2013 to escape the violence that has since shattered their hometown, Idlib. With their wives and children, they moved across the border and opened a gleaming new bakery in the southern Turkish city of Hatay, in a neighborhood that now is so teeming with Syrians that it evokes comparisons to Damascus before the war. Their 25 employees are also Syrian refugees.

“What this shows to me, and to the world, is that refugees can contribute to a country,” Linda Thomas-Greenfield, the American ambassador to the United Nations, said this week at the bakery, in front of stacks of pistachio rolls and baklava dripping with honey.

“The message they have heard from me is that we have not forgotten Syria,” she said as the brothers stood nearby.

It also was a pointed message to the government of Turkey, which wants to move many of the 3.7 million Syrian refugees in the country back across the border.

In an already strained economy, many Turks have blamed refugees for accepting lower wages so that they are hired for a limited number of available jobs in the country. Hard-line politicians have long accused Turkey’s president, Recep Tayyip Erdogan, of having an open-door policy that they say allowed “an invasion” of Syrians, Afghans and others escaping conflicts.

Mr. Erdogan has promised to send at least some refugees back, and this week he threatened a new military offensive in Syria against Kurdish fighters, in part to clear a safe passage for the refugees’ return.

The United States has criticized the planned Turkish assault, which targets Kurdish fighters in northern Syria in a conflict that long predates the civil war that began in 2011. On Wednesday, Secretary of State Antony J. Blinken warned that a Turkish incursion would further destabilize the region.

It could also force more Syrians to flee — as could the possible closure of a route that the United Nations uses to deliver food, water, medicine and other supplies to millions of people in Idlib province in northwestern Syria.

Peace talks that had been shepherded by the United States and Russia have been stalemated for years, underpinning a decade of human devastation and diplomatic disappointments.

After 11 years of war, Syria has become a cautionary example of what can happen in a conflict with no end in sight, like the one that began 100 days ago in Ukraine.

“The world’s outreach is absent,” said Ammar al-Selmo, a member of the White Helmets, a rescue organization that operates in rebel-held areas in Syria, mostly in the country’s northwest.

“There is no action on Syria,” he added, “and I’m so sorry to say this war has moved to Ukraine — the same tactic of war, happening right now in Ukraine, the same suffering.”

“What happened in Syria is a rehearsal for what happened in Ukraine later,” Mr. al-Selmo said.

Ms. Thomas-Greenfield spent two days in Hatay this week, and traveled to the Syrian border, to assess the potential fallout should the United Nations be forced to end its aid deliveries to Idlib in July, as many diplomats and relief workers anticipate. Already, U.N. officials are emptying their warehouses to stockpile aid in Syria in case Russia vetoes an annual Security Council measure that would allow deliveries to continue for another year.

Russia, a benefactor of President Bashar al-Assad of Syria, has accused the international aid deliveries of violating Syria’s sovereignty while supporting extremists in Idlib. In a recent interview, the deputy Russian ambassador to the United Nations, Dmitry Polyanskiy, cast doubt that the U.N. deliveries would continue, given that sticking points over the mission in years past had been smoothed over only in last-minute negotiations with the United States.

Diplomatic talks between the United States and Russia have all but halted since Moscow invaded Ukraine in February. But Ms. Thomas-Greenfield said she would try to reopen discussions with Russian diplomats at the U.N. to preserve the aid — and to ensure that Moscow does not use it as a bargaining chip with other nations to gain leverage in Ukraine.

Mark Cutts, the U.N. relief coordinator for Syria, said the humanitarian aid operation was the largest in the world, with more than 56,000 truckloads of lifesaving supplies delivered since 2014. As many as four million people in Syria — including an estimated 1.7 million living in tents — receive supplies that are delivered to Idlib, the last large rebel enclave in Syria and an area that has also become a haven for extremists linked to Al Qaeda.

“No one should have to live in tents for more than a decade,” Mr. Cutts said. “And we’re already not providing the assistance that’s needed.”

Ms. Thomas-Greenfield put it more bluntly. Without the aid, she said, “babies will die.”

On the Turkish side of the border, known as Point Zero, the deputy governor of Hatay, Orhan Akturk, said the amount of assistance seemed to be lower than in the past. The U.N. mission “should be extended,” he said. “That’s important, given the alternative.”

The United States and Turkey, both members of NATO, have formed an uneasy alliance over the last decade as Mr. Erdogan has sought to stifle political opposition and free speech, drawing American condemnation. A belief among many Turks that the United States played a shadowy role in the failed coup attempt against Mr. Erdogan in 2016 fueled the tensions.

Both countries oppose Mr. al-Assad’s grip on power but are bitterly divided over Kurdish fighters in northern Syria. Turkey considers them terrorists, but the United States views them as partners who helped beat back the Islamic State.

More recently, Mr. Erdogan has blocked Sweden and Finland from joining NATO, aligning with Russian opposition to expanding the military alliance.

Ms. Thomas-Greenfield spoke Thursday with Sedat Onal, a Turkish deputy foreign minister. A description of the conversation, released by her office, said the two agreed on the importance of keeping U.N. aid flowing to Syria. It also noted the American opposition to the upcoming Turkish offensive against the Syrian Kurds.

Human rights advocates have for years accused Mr. Erdogan of deporting refugees, in violation of international laws, and relocating them in areas in Syria near the border where Turkish forces have pushed out Kurdish fighters.

In an interview later Thursday, Ms. Thomas Greenfield said it was “wishful and hopeful thinking” for Turkey to try to justify returning refugees to so-called safe zones where many of the Syrians have never lived.

She added: “Refugees will determine whether it is safe for them to go back.”

Mr. Erdogan’s government has already begun building an estimated 100,000 brick houses in Idlib for the returning refugees and other Syrians in a process that Turkey’s interior minister, Suleyman Soylu, said as recently as Wednesday would be voluntary. Mr. Erdogan has also pledged to build schools and hospitals in Syria to entice refugees to voluntarily return.

“We are not going to leave humanity alone. We are not going to turn our backs to our neighbors,” Mr. Soylu said Wednesday in Ankara, the Turkish capital. But, he said, “we know that it is not possible for us to carry another wave of migration,” and he accused Western governments of failing to offer solutions.

In Hatay, the 67-year-old Mohammed Faisal said he could not go back to Syria.

He survived 15 years in jail for speaking out against the Syrian government and another four years of civil war before escaping in 2015 to Turkey, where he feels safe.

People still living in Syria are “in a very hard situation,” said the man, who did not want to be identified by his full name for fear of reprisal.

Without international aid, he said, “you can consider these people as dead.”

Safak Timur in Istanbul contributed reporting.

By Lara Jakes/ The New York Times