The United States understands Türkiye's "legitimate concerns" about the threat posed by the PKK terrorist group in northeastern Syria, the State Department said Tuesday.

"We understand the very legitimate concerns that Turkey has about the terrorist threat that the PKK poses. We understand the very legitimate concerns that Turkey has about the presence of foreign fighters inside Syria, and so we're talking to them (Türkiye​​​​​​​) about those concerns and trying to find a path forward," spokesman Matthew Miller said at a news conference.

He said the U.S. wants to see the "establishment of a Syrian national government that encompasses all of the various ethnic groups inside Syria."

"And at the end of that, you don't have any subnational militias, any subnational groups who are carrying arms under their own banner. And as part of that, we certainly think it's appropriate to discuss the expulsion of foreign fighters," he added.

The U.S. repeatedly said it would maintain support for the terrorist PKK's Syrian offshoot YPG-led SDF, its primary Syrian partner in the fight against the Daesh terror group, adding that the Biden administration wants to maintain the focus on the anti-Daesh fight.

U.S. support for the SDF has significantly strained relations between Washington and Ankara.

Regarding a question about what the new administration should look like in Syria following the takeover of a new transitional government that ousted the Bashar Assad regime, Miller said: "That is a decision for the Syrian people to make."

"What we believe is Syrian people decide the type of government, and the Constitution, a framework that represents their aspirations, that represents the kind of normal compromises in a give and take that happen in civil society," said the spokesman.

Miller said the new Constitution should be inclusive, transparent and accountable.

Assad, Syria's leader for nearly 25 years, fled to Russia after anti-regime groups took control of Damascus on Dec. 8, ending the Baath Party regime, which had ruled Syria since 1963.

Meanwhile, Miller also said the cease-fire between the Türkiye-backed opposition and SDF around the northern Syrian city of Manbij has been extended until the end of this week.

Washington brokered an initial cease-fire last week but it had expired, Miller said, adding that Washington would like the cease-fire to be extended for as long as possible.

"We continue to engage with the SDF, with Turkey about a path forward," Miller said.

"We don't want to see any party take advantage of the current unstable situation to advance their own narrow interests at the expense of the broader Syrian national interest," he added.