The United States has hailed the fall of President Bashar al-Assad's regime, and called for him to be held accountable.

President Joe Biden says Washington will work with Syrian groups to establish a transition, but warned of possible risks ahead.

Meanwhile, the US says it carried out dozens of air strikes on ISIL targets in Syria.

The US Central Command says the strikes were aimed at ensuring ISIL does not take advantage of the fall of Assad's regime.

Al Jazeera’s Heidi Zhou-Castro has more from Washington, DC.