FILE PHOTO - A convoy of Islamic State fighters and their families begin to depart from the Lebanon-Syria border zone in Qalamoun, Syria August 28, 2017. REUTERS/ Omar Sanadiki

WASHINGTON (Reuters) - The U.S.-led coalition fighting Islamic State said on Friday its surveillance aircraft had moved away from an Islamic State convoy which has been trying to reach territory in east Syria.

The Islamic State convoy has split in two, with 11 buses remaining in the open desert after others turned back into government-held areas.

The Syrian government and Lebanon’s Hezbollah group offered the convoy of originally about 300 lightly armed Islamic State fighters and about 300 family members safe passage in return for the militant group surrendering an enclave on the Syria-Lebanon border.

However, the coalition has blocked the convoy from entering Islamic State territory in east Syria, near the border with Iraq, by cratering roads and destroying bridges.

“To ensure safe de-confliction of efforts to defeat ISIS, coalition surveillance aircraft departed the adjacent airspace at the request of Russian officials during their assault on Dawyr Az Zawyr,” the coalition said in the Friday statement, using an acronym for Islamic State.

The coalition said Syrian pro-regime forces had “advanced past” the convoy.

“The regime’s advance past the convoy underlines continued Syrian responsibility for the buses and terrorists,” Brigadier General Jon Braga, director of operations for the coalition said.