US-led forces today bombed the route traveled by Islamic State (IS) fighters withdrawing from the Lebanese border under a cease-fire deal with Hezbollah, leaving them stranded in territory controlled by Syrian President Bashar al-Assad’s forces.

Some 300 fighters and their families were being bused to Syria’s IS-controlled Deir ez-Zor province near the border with Iraq under the agreement reached earlier this week. The airstrikes took out a small bridge and cratered the road through Syria, while also taking out another group of IS fighters on their way to meet the convoy.

“The coalition was not party to any agreement between the Lebanese Hezbollah, the Syrian regime and [IS],” Col. Ryan Dillon, a coalition spokesman, said in a statement. “Russian and pro-regime counter-[IS] words ring hollow when they cut deals with and allow terrorists to transit territory under their control.”

Dillon said the airstrikes did not hit the convoy itself, in accordance with international law, but had successfully halted the advance of IS fighters heading east between Hamaymah and al-Bukamal. The bombed road leads to the Iraqi border and the strategically important city of Qaim in the Euphrates River Valley, where Iraqi security forces are planning an offensive to clear the area.