As US-backed forces take victory laps in the Islamic State’s (IS) self-proclaimed capital of Raqqa, the Pentagon is considering extending its presence deeper into Syria, a move that could bring US troops into contact with pro-regime forces.

Col. Ryan Dillon, a spokesman for the US-led mission fighting the terror group, told reporters that the international coalition is in talks with Syrian Democratic Forces (SDF) commanders about continuing the campaign into IS-held areas along the Euphrates River following today’s victory in Raqqa. He said the more than 600 US troops currently training and assisting the SDF won’t be staying in Syria “indefinitely,” but acknowledged that “there still is fighting that is left to be done.”

For now that fighting is taking SDF units straight to Deir ez-Zor, where an alliance of soldiers loyal to Bashar al-Assad, Russian troops and Iran-backed Shiite troops are trying to grapple territory back from IS and anti-regime rebels. And while the Pentagon is considering extending de-confliction agreements with Russia to cover a wider swath of Syria, former US officials say it will be difficult for the US military to avoid getting enmeshed in the politics of the wider war. 

“You don’t want to deploy US forces willy-nilly and find them in the middle of conflict,” Robert Ford, a former US ambassador to Syria, told Al-Monitor. “It’s kind of a mission creep beyond going to get [IS]. They’re going to have to be dealing — as much as they don’t want to — with the politics of the Syrian civil war. It’s just unavoidable now.”