Syria's government said a drone strike by the Kurdish-led Syrian Democratic Forces killed seven of its soldiers on Wednesday, though the SDF denied this, in an incident that threatens to derail a ceasefire after days of fighting in the northeast.
The Syrian army called the attack, which it said took place as soldiers were securing a captured military base containing explosives, a dangerous escalation.
The SDF, previously the main US ally in Syria, said it had not carried out a strike and that the blast had occurred when Syrian soldiers were moving explosives. It accused the Syrian army of violating the truce with attacks in several locations.
After days of rapid gains, the government on Tuesday said it had reached an understanding with the SDF for the SDF to agree to a four-day ceasefire to integrate into the central state, and that, otherwise, the SDF would face an assault on the two last main cities it holds.
How Syria's government has redrawn map with advances against the Kurds
The Syrian government has seized swathes of northern and eastern Syria from Kurdish forces, consolidating President Ahmed al-Sharaa's rule nearly 14 months after Bashar al-Assad was toppled.
The rapid turn of events has brought almost all of Syria back under the authority of the Damascus-based state, following years of conflict that fractured the country, and puts a spotlight on shifting US policy.
What triggered the Syrian army advances?
Tensions had been simmering between the government and the Kurdish-led Syrian Democratic Forces for months.
Damascus has demanded that the SDF, spearheaded by the Kurdish YPG, merge fully into the security forces and that governing bodies in the Kurdish-run regions also be integrated.
The Kurdish-led forces have resisted, aiming to preserve their regional autonomy and expressing concerns that the Islamist-led administration in Damascus seeks to dominate Syria.
Conflict erupted this month, with government troops seizing Kurdish-run districts of Aleppo before thrusting eastwards last week, forcing Kurdish fighters to retreat.
What is the US position?
While the US military built close ties with the SDF, Washington never backed the SDF's political goal of securing a high degree of autonomy for the northeast.
US policy has been complicated by objections from NATO member Turkey, which deems the YPG an extension of the outlawed Kurdistan Workers Party (PKK) and sent troops into Syria several times to counter its influence.
With Assad toppled, US President Donald Trump has developed close ties to Sharaa, lifting sanctions and welcoming Syria into an international anti-Islamic State coalition.
US envoy Tom Barrack said on Tuesday the original purpose of the SDF had largely expired, and that the US had no long-term interest in retaining its presence in Syria.
Barrack described the offer of integration into the central state with citizenship rights, cultural protections, and political participation as the "greatest opportunity" the Kurds have.
Trump on Tuesday also appeared to back Sharaa, saying he was "working very hard", adding that Washington was also "trying to protect the Kurds."