Syria's most powerful rebel leader Abu Mohammed al-Golani urged Iraqi Prime Minister Mohammed Shia al-Sudani not to allow the country's Iran-aligned Popular Mobilization Forces (PMF) to intervene in Syria, in a video statement posted on Thursday.

The PMF, known as the Hashd al-Shaabi in Arabic, contains many Iran-backed armed factions that previously fought in Syria to help Syrian President Bashar al-Assad retake territory that fell to rebels in the early years of the Syrian war.

"We urge and hope Iraqi politicians, first and foremost Mohammed Shia al-Sudani... do their duty to prevent the Iraqi Hashd al-Shaabi's intervention in what is happening in Syria," Golani said.

The PMF has said that it is not deployed in Syria, and commanders within it have said they would only do so on orders from their leadership.

Reuters reported earlier this week that several hundred Iraqi militia fighters had deployed to Syria to help the government fight rebels who seized Aleppo last week.

Golani said the fighting in Syria would not expand to Iraq and said rebel forces wanted strategic economic and political relations with Baghdad after overthrowing the current regime.