Iran recalled 275 soldiers from a special unit operating in Syria, London’s Sunday Times reported, a move that could be linked both to the worsening economic crisis in Tehran and to Iran’s wavering faith in the survival of Bashar Assad’s regime.

The fighters reportedly belong to the Revolutionary Guard Corps’ elite Quds Force. They were in Syria to help Assad’s military in its crackdown on opposition rebels, according to the report.

The report cited Western intelligence officials saying the fighters were flown out of Syria last week, and said the information was confirmed by a relative of a Quds Force member.

The move gave rise to speculation that the decision reflects both Tehran’s economic woes and its weakening faith in Assad’s ability to win the country’s 18-month long civil war.

On Sunday, Syrian troops pressed their offensive to retake rebel-held areas in the northern city of Aleppo, as well as in Homs, towns around the Syrian capital of Damascus and southern villages on the border with Jordan, according to the London-based Syrian Observatory for Human Rights.

The group said there were casualties in Sunday’s fighting, but did not give figures.

Syrian state TV reported Sunday that soldiers clashed with two armed groups that infiltrated from Lebanon on Saturday, killing several fighters.

The clashes took place in the suburbs of the central city of Homs, which is near the Lebanese border. Syrian forces reportedly chased the groups back into Lebanon.