The Syrian army and allied forces are close to breaking a three-year siege imposed by ISIL fighters on parts of the eastern city of Deir Az Zor, according to state-run media.

ISIL, or the Islamic State of Iraq and the Levant group, controls most of Deir Az Zor province - apart from a Syrian government-held enclave in Deir Az Zor city and a nearby military air base.

Pro-government forces have been advancing towards the city on multiple fronts for weeks, and are now within 3km of the enclave, state television reported on Monday.

A military media unit run by the government's ally Hezbollah said the advancing forces were heading to the besieged military camp on the city outskirts.

"The siege on government troops will be broken within hours," a military source told AFP news agency.

Al Jazeera's Mohammed Jamjoom, reporting from Beirut, the capital of neighbouring Lebanon, said that breaking the siege would be a "very significant" development for the Syrian government and "quite a setback" for ISIL.

"In the last several weeks, it's been reported that ISIL has lost more than half of its self-proclaimed capital of Raqqa in Syria," he said.

"Deir Az Zor, in the east of the country, is really their last remaining post in Syria - there are still large parts of Deir Az Zor province that are strongholds for ISIL fighters.

"If the government is going to be able to breach this siege, that is going to be a problem for ISIL if they are going to retain other territories."

Mohamed Ibrahim al-Samra, Deir Az Zor's governor told Syria's state news agency Sana that besieged residents were celebrating as pro-government forces approached.

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"Yesterday, Deir Az Zor city saw celebrations and rejoicing among all segments of society in advance of the expected victory with the advance of the Syrian Arab Army to the outskirts of the besieged city," he said.

The Syrian Observatory for Human Rights (SOHR), a UK-based group monitoring the country's conflict via a network of contacts on the ground, said that more than 10,000 people remain in parts of the city held by ISIL.

In government-held sections of Deir Az Zor, the population has plummeted to around 100,000 people from prewar numbers of some 300,000.



Deir Az Zor borders Iraq, where ISIL has already faced heavy defeats in their former strongholds of Mosul and Tal Afar.