Senior U.S. officials are concerned that a new Syrian military offensive against Kurdish forces could expand into a broader campaign against the U.S.-backed militia, threatening to destabilize Syria and further divide two crucial U.S. security partners fighting Islamic State.

The Syrian army operations command said Friday night that it was striking forces allied with the Kurdish-led Syrian Democratic Forces in the town of Deir Hafer, east of Aleppo. The statement came after days in which the government surged military forces to the area. The SDF said in a statement just after midnight local time that it was withdrawing its forces from the area in a show of good faith following calls from foreign powers mediating in the dispute.

U.S. intelligence agencies have assessed that Syrian President Ahmed al-Sharaa is planning a multipronged operation, backed by the Turkish military, against the SDF in the eastern part of the Aleppo province and potentially across the Euphrates River, according to two U.S. officials. Such an operation could extend the fighting into northeastern Syria, where most U.S. forces are deployed.

In a sign of how serious the situation has become, U.S. military forces arrived Friday in Deir Hafer to meet with Syrian partners after days of deadly clashes, according to Capt. Tim Hawkins, a spokesman for the U.S. Central Command.

The U.S. forces will “temporarily assess what is happening on the ground, engage Syrian partners, and help stabilize the situation,” Hawkins said. “A Syria at peace with itself is critical to preserving peace and stability across the region.”

Damascus’ forces began bombing Deir Hafer this past week and urged civilians to evacuate the area.

The semiautonomous Kurdish region of northeastern Syria remains a major obstacle to Sharaa’s consolidation of control over Syria after the collapse of the Assad regime in 2024. Turkey, meanwhile, has long had designs to get rid of Kurdish fighters who are affiliated with the Kurdistan Workers’ Party, also known as the PKK, which both Turkey and the U.S. view as a terrorist group.

Sharaa and the SDF’s leader signed a pact last March to merge the SDF into the Syrian military, but the deal lacked details and negotiations toward a final agreement have stalled out in recent months.

A broader conflict between the Syrian government and the Kurdish-led SDF would pose a serious challenge for the Trump administration and the U.S. military, which have encouraged the SDF to join the new government in Damascus after the fall of former President Bashar al-Assad in December 2024.

Lawmakers and U.S. military officials are particularly concerned that if the fighting extends into northeastern Syria, the Syrian Kurdish fighters guarding hundreds of Islamic State prisoners in facilities across the region will leave their posts, resulting in the escape of many.

U.S. intelligence officials are debating the scope of the potential operation, one of the officials said. Some officials believe Sharaa plans to limit the fighting to Aleppo province, but others think he is eyeing a broader operation involving troops moving from the west to the Euphrates and south from the border with Turkey, the official said. Military intelligence officials believe that Sharaa has already approved the larger operation, the official said.

Other Western officials monitoring the situation have also assessed that the offensive will be limited to the area around Deir Hafer south of the Euphrates River. But any fighting could spill over to other areas along the front line, according to security analysts.

President Trump’s special envoy for Syria, Ambassador Tom Barrack , and Adm. Brad Cooper, the head of U.S. Central Command, have been engaging daily with both sides to head off a larger offensive, one of the officials said. Vice President JD Vance spoke to Sharaa to urge him to resolve differences with the Kurds, according to a person familiar with the conversation.

U.S. officials have threatened to reimplement Caesar Act sanctions against the Syrian government if Damascus goes ahead with the broader attack, the official said.

“The United States remains in close contact with all parties in Syria, working around the clock to lower the temperature, prevent escalation, and return to integration talks between the Syrian government and the SDF,” Barrack said on social media Friday.

Barrack worked to impose a cease-fire in a recent round of fighting between the government and SDF in Aleppo. That battle resulted in SDF fighters’ leaving Aleppo, abandoning a small redoubt in one of Syria’s largest cities.

Deir Hafer is one of the last regions south of the Euphrates controlled by the Kurdish forces, which seized the territory during the chaos after the fall of Assad. The government this week released video of a column of military vehicles heading to the front.

The U.S. has had a longstanding partnership with the SDF to combat Islamic State, or ISIS. The alliance has posed a geopolitical challenge for the U.S. because the group includes members of the PKK.

“I hope issues are resolved through dialogue, but if dialogue fails, I see that the Syrian government may consider the use of force as an option to preserve unity and order,” Turkish Foreign Minister Hakan Fidan said Thursday.

The U.S. has hundreds of soldiers stationed in Syria as a part of the fight against ISIS, with most of those forces in the northeastern part of the country controlled by the SDF. Their presence in the country is a major deterrent against wider war with government forces.

The new Syrian government joined the U.S.-led coalition against Islamic State in November as a part of an emerging partnership with Washington. Trump ordered a removal of U.S. sanctions on Syria and welcomed Sharaa to the White House as he tries to stabilize the country after the fall of Assad.

Trump’s approach to Syria has unsettled the country in the past. In 2019, he ordered a removal of U.S. forces from the country, resulting in a Turkish military operation that took control of a swath of territory along its border with Syria. Trump reversed the decision weeks later.

Sen. Lindsey Graham (R, S.C.) posted on social media on Thursday that he is “growing increasingly concerned” that Damascus was partnering with Turkey to attack the Syrian Kurds, and added that the Kurdish fighters control 9,000 Islamic State prisoners across the country.

“I support a fair chance for the new Syrian government, however if there’s an escalation of attacks against the Kurds by Syrian forces supported by Turkey, this will create a whole new dynamic,” Graham said. “If anyone believes that I or any of my colleagues would be comfortable—at this stage—for the ISIS prisoners to be guarded by the Syrian army or Turkey instead of the Kurds, you are sadly mistaken. Choose wisely.”