ISTANBUL — Forces loyal to Syrian President Bashar al-Assad advanced Monday into several key towns across northeastern Syria after an 11th-hour deal with local Kurdish fighters, dramatically altering the balance of power inside the war-battered country.
The swift Syrian advance was set in motion by President Trump’s abrupt decision in recent days to withdraw U.S. troops from northeastern Syria, leaving Kurdish forces long allied with the United States vulnerable to attack from the Turkish military.
Turkey has been pressing an offensive against Syrian Kurdish fighters because of their links to Kurdish militants inside Turkey. The military campaign has been condemned by many of Turkey’s Western allies, including the United States, which have warned in part that the escalating violence could give the Islamic State a chance to regenerate its insurgency less than a year after the militant group’s territorial “caliphate” was defeated.
Trump on Monday imposed sanctions on Turkey’s Defense and Energy ministries, as well as three senior Turkish officials, because of their involvement in the incursion and resulting humanitarian crisis. He also said he would raise tariffs on Turkish steel to 50 percent and halt negotiations on a new trade deal with Turkey.
Defense Secretary Mark T. Esper blasted Turkey for ignoring U.S. objections in launching a campaign “that has resulted in widespread casualties, refugees, destruction, insecurity and a growing threat to U.S. military forces.”
European foreign ministers also condemned the Turkish incursion Monday and agreed on an informal, E.U.-wide ban on arms sales to Ankara. The European leaders warned that the instability caused by the Turkish offensive would provide the Islamic State with a new toehold, posing a direct threat to Europe.
The military campaign is taking a huge toll on tens of thousands of Syrians, with the United Nations reporting that as many as 160,000 people, including 70,000 children, have been displaced since the fighting in northeast Syria escalated nearly a week ago.
As the violence has spiked, aid agencies have been scaling back or suspending humanitarian operations because of shelling, road closures and other threats. All international aid groups have now withdrawn their personnel, according to the Kurdish Red Crescent.
“This is our nightmare scenario. There are tens of thousands of people on the run, and we have no way of getting to them,” said Made Ferguson, deputy country director for Syria at Mercy Corps, a U.S.-based aid agency. “The humanitarian crisis is worsening by the day, and now aid workers are cut off from providing lifesaving assistance to the most vulnerable.”
In an effort to prevent Turkey and its rebel proxies from seizing territory in northern Syria, Kurdish authorities reached a surprise agreement with the Syrian government to return Assad’s forces to the northeast of the country. Government forces lost control of the territory amid the civil war that erupted after the Arab Spring protests of eight years ago.
The Syrian deployments represent a stunning reversal for the Kurdish-led administration and allied Syrian Democratic Forces (SDF), which had partnered with the United States to battle the Islamic State in the area.
The deal was made to allow Syrian government forces to take over security in some border areas, according to Syrian Kurdish officials, who said their administration would maintain control of local institutions.
Syria’s government, however, sees the agreement as effectively killing Kurdish ambitions to establish a de facto state in the country’s northeast, said Kamal Jafa, a pro-government military analyst in the Syrian city of Aleppo. The government “managed to find a way to reestablish control over one-third of Syria without firing a bullet,” he said. “The key thing is the Syrian army’s intervention has ended the prospect of a de facto Kurdish state.”
As the two sides tussled over the specifics, Turkish-backed forces operating under the Syrian National Army, an umbrella group of rebel factions, announced the start of an operation to retake the northern city of Manbij from the SDF.
Turkey had long demanded that the United States expel the SDF from Manbij and complained that a deal struck with Washington to remove the fighters was not being implemented.
Turkey and the United States agreed in December on a plan for the Kurdish-led SDF to withdraw from Manbij, about 25 miles west of the Euphrates River, and a road map envisioned joint U.S.-Turkish patrols in the city. Turkish officials view the Kurdish fighters in Syria as terrorists because of their links to the Kurdistan Workers’ Party (PKK), which has waged a decades-long war for autonomy inside Turkey.
A U.S. official with knowledge of operations in Syria said Monday that American troops remained in Manbij. But by early Tuesday in Syria, a second U.S. official said they had departed.
The second official said that preparations were underway to consolidate forces and leave the country. It is likely that the SDF will strike a deal with Russian forces to bolster security in the face of the Turkish offensive, the official said.
“The Turks going in is not good for Manbij,” he said.
Earlier Monday, the official said, U.S. troops communicated with forces loyal to Assad as they advanced toward Manbij. He said the convoy may have included Russian troops or mercenaries, both of which have backed Assad’s forces in their battle against Syria’s rebels.
“They turned them around when we told them we were still in the area,” the U.S. official said of Syrian government troops.
A second U.S. official with knowledge of military operations in Syria said it was likely that Russia, a key ally of Syria’s government, would move into Manbij after U.S. troops left.
The situation in northeast Syria has become highly unpredictable since Turkey began its offensive last week, hitting towns and cities with artillery and airstrikes while ground troops advanced and captured territory.
Of particular concern to the United Nations and other agencies are the thousands of people housed in detention camps across the northeast, including family members of Islamic State militants.
On Sunday, hundreds of relatives of Islamic State fighters escaped a detention camp in Ain Issa after Turkish shells hit the area. The U.N. Office for the Coordination of Humanitarian Affairs said it had “grave concerns” for the population of the camp, which hosts about 13,000 civilians.
SDF forces guarding al-Hol, a sprawling camp holding some 70,000 people disgorged from the Islamic State’s final scrap of territory, have also pulled back as fighters are diverted to the front lines with Turkey.
“It’s quiet in the camp for now, but we’re all scared of the uncertainty,” said a medic, speaking on the condition of anonymity because she was not authorized to talk to the media. “We thought that America would protect us here. Why are they walking away?”
Dadouch and Khattab reported from Beirut. Lamothe reported from Washington. Kareem Fahim in Istanbul and Louisa Loveluck in Irbil, Iraq, contributed to this report.