A member of the U.S.-backed Syrian Manbij Military Council, left, speaks with a U.S. soldier in north Syria, on April 4. (Hussein Malla/AP)

Years of U.S.-led battles to root the Islamic State from its Syrian strongholds have sent tens of thousands of civilians pouring into camps across the country’s northeast, exhausted, fearful and with nowhere else to turn.

President Trump’s announcement Wednesday that American troops will pull out of the country “quickly” now risks imperiling the efforts by aid workers to pick up the pieces.

Humanitarian agencies in Syria have moved rapidly to deal with what could be ahead.

Relief teams were temporarily relocated Thursday to towns farther east and away from the possible front lines if Islamic State fighters attempt to reclaim territory or Turkish forces stream over the border to challenge U.S.-allied Kurdish militias.

“This is crazy,” wrote one aid worker in a text message.

“We had no idea,” wrote another in messages shared on the condition of anonymity because the workers were not authorized to speak directly to the news media.

As temperatures drop and winter storms swirl, a network of international and local aid groups is supporting the more than 35,000 civilians in sprawling displacement camps in Syria’s northeast — a region bordered by Turkey and Iraq.

The area offered the only haven as U.S. forces — aided by airstrikes and Syrian Kurdish and Arab fighters on the ground — gradually pushed back the Islamic State from strongholds including its de facto capital of Raqqa, about 250 miles northeast of Damascus.

Many civilians fled after their homes were destroyed. 

In a region that is still trying to recover, the agencies are feeding people, providing economic assistance and propping up a shattered health and education system. Wednesday’s shock announcement that some 2,000 U.S. troops could soon leave northern Syria raises the prospect that fresh violence and instability could force the aid operation to retrench.

“The most immediate concern is the safety and well-being of our staff,” said one humanitarian worker, speaking on the condition of anonymity, like most interviewed for this article, because of the sensitivity of the situation. 

“We don’t want to be suspending any operations if we don’t have to.”

Trump’s announcement that U.S. forces will soon leave came days after Turkish President Recep Tayyip Erdogan threatened to send troops across the border to attack Kurdish fighters there. Washington’s decision to make the Kurdish fighters a key partner in the fight against the Islamic State has rattled Turkey, which has battled Kurdish separatists at home for decades.

Although U.S. officials had previously described any military operation against the Syrian fighters as “unacceptable,” Wednesday’s announcement could embolden Turkey to follow through with military operations.

Most aid groups said that they were making no changes to their programming in the short term but that they would be monitoring the U.S. withdrawal carefully for signs of potential risk.

But many expressed concern that a Turkish military incursion could require the aid response to scale up, not down.  

The International Rescue Committee said Thursday that hundreds of thousands of people could flee their homes and lose access to vital aid and health care if a military offensive began. 

“Families are struggling to get their lives back on track, and many are still reliant on vital aid,” said Mark Schnellbaecher, the group’s Middle East regional director. “The major powers involved in Syria must consider the humanitarian consequences of all planning decisions.”

Representatives of the Kurdish authorities that control the U.S.-protected zone promised aid officials Thursday that they would be notified of any potential security concerns and that support for an evacuation would be provided if necessary, according to minutes from the meeting in northeastern Syria. 

But privately, humanitarian workers suggested that the Kurdish authorities may be overwhelmed.

“Kurdish authorities just don’t have the capacity to deal with needs this big,” said one aid worker. “The people we’re supporting here are the most vulnerable of the vulnerable. They don’t have anything to go back to.”