Turkish-backed opposition fighters were advancing on Saturday towards the northern Syrian town of Dabiq, a symbolically important stronghold, with the aim of taking it from Islamic State (IS) militants, Turkey's president said.

The small town holds great value to IS because of a prophecy of an apocalyptic battle, and features heavily in its propaganda, the BBC said.

"We are now advancing. Where? To Dabiq," President Recep Tayyip Erdogan said in televised comments in the Black Sea province of Rize.

Turkey launched an unprecedented operation inside Syria on 24 August, helping Syrian rebels to rid its frontier of IS militants and Syrian Kurdish militia.

In the operation's early weeks, Jarabulus and al-Rai became the first two major settlements to be captured from the IS.

Footage shows Turkey-backed Free Syrian Army fighters preparing to take on ISIS in Dabiq, epicenter of their eschatological vision. https://t.co/91T14cVSNM — Borzou Daragahi 🖊🗒 (@borzou) October 15, 2016

The Syrian rebels, supported by Turkish planes and tanks, are about 2km from Dabiq, according to the British-based Syrian Observatory for Human Rights.

"Two hours ago, the rebels started their attack to control Dabiq. The rebels came from al-Rai," it said.

Dabiq holds symbolic importance for IS because of a Sunni prophecy saying it will be the site of an end-of-times battle between Christian forces and Muslims.

The town itself has negligible military value compared with the strategic IS-controlled cities of Raqqa in Syria and Mosul in Iraq.

Earlier this week, IS tried to downplay the advancing rebel forces in its al-Naba online pamphlet, saying the major battle for the town was yet to come.

Anti-IS fighters and their Turkish backers "have amassed in Aleppo, announcing Dabiq as their major goal," and thinking they can score "a great moral victory against the Islamic State".

But "the great epic of Dabiq will be preceded by great events and apocalyptic omens," the pamphlet, published on Thursday, said.

"These hit-and-run battles in Dabiq and its outskirts - the lesser Dabiq battle - will end in the greater Dabiq epic," the group added.

Dabiq is also the name of IS's sleek English-language magazine. Every new edition opens with a quote by Abu Musab al-Zarqawi, the late leader of IS's precursor, the Islamic State of Iraq.

"The spark has been ignited in Iraq, and its flames will grow until they burn the crusader armies in Dabiq," he once said.