"We urge him (Sudani) to distance Iraq from entering the new furnace of what is happening in Syria," said Jolani, head of the Islamist group Hayat Tahrir al-Sham (HTS), in a video message posted on the opposition faction leadership's Telegram channel.

Iraq's powerful Iran-aligned Kataeb Hezbollah armed group on Monday called on Baghdad to send troops to Syria to support the Damascus government. Kataeb Hezbollah is part of Hashed al-Shaabi, an alliance of Iran-backed former paramilitary groups now integrated in Iraq's regular armed forces.

Jolani urged Sudani to "prevent the Iraqi Hashed al-Shaabi from interfering in what is happening in Syria".

He added: "There are many fears and illusions -- that some Iraqi politicians believe -- that what is happening in Syria will extend to Iraq. I say firmly that this is 100 percent wrong."

The Hashed al-Shaabi, also known as the Popular Mobilisation Forces, is under the Iraqi prime minister's command and denies involvement outside Iraq's borders.

Kataeb Hezbollah has previously fought in Syria alongside forces loyal to President Bashar al-Assad.

On Monday, Iraq said it had sent armoured vehicles to bolster security along its 600-kilometre (370-mile) border with Syria.

Sudani told Assad on Saturday that his country's security is "closely linked to Iraq's national security" while playing a "crucial role in regional security and efforts to establish stability in the Middle East," Sudani's office said.

The Syrian Observatory for Human Rights, a Britain-based war monitor, earlier this week reported about 200 pro-Iranian Iraqi fighters entered Syria to back government forces.

Iraq remains scarred by the rise of the Islamic State group in 2014, which saw the jihadists capture nearly a third of the country before local forces backed by a US-led coalition defeated them in 2017.