Beirut:The Syrian army intends to advance into IS-held Raqqa province having captured positions at the provincial border of the extremists' stronghold, a Syrian military source said on Saturday.
A move into Raqqa province would reestablish a foothold for Damascus in a region where it has had no presence since August 2014.
The military source who was briefed on the matter said the operation had been going on for a number days.
The army had captured several positions from IS at the provincial border between Hama and Raqqa in the last two days.
"It is an indication of the direction of coming operations towards Raqqa. In general, the Raqqa front is open... starting in the direction of the Tabqa area," the source said.
Tabqa is the location of an air base captured by IS in 2014.
The army had moved to within 35 km (20 miles) of the base.
The Syrian Observatory for Human Rights, which monitors the war, earlier reported the army's had advanced to the provincial borders of Raqqa.
Meanwhile, Russia said on Saturday a ceasefire deal for Syria agreed by major powers was more likely to fail than succeed while Syrian government forces backed by further Russian air strikes gained more ground against rebels near Aleppo.
International divisions over Syria surfaced anew at a Munich conference where Russia rejected French charges that it was bombing civilians, just a day after world powers agreed on the "cessation of hostilities" due to begin in a week's time.
The cessation of hostilities deal falls short of a formal ceasefire, since it was not signed by the warring parties - the government and rebels seeking to topple President Bashar Al Assad in a five-year-old war that has killed 250,000 people.
If its forces retake Aleppo and seal the Turkish border, Damascus would deal a crushing blow to the insurgents who were on the march until Russia intervened, shoring up Assad's rule and paving the way to the current reversal of rebel fortunes.
Russia has said it will keep bombing IS and the Al Qaeda-linked Nusra Front, which in many areas of western Syria fights government forces in close proximity to insurgents deemed moderates by Western states.
Russian Foreign Minister Sergei Lavrov, asked at a security conference in Munich on Saturday to assess the chances of the cessation of hostilities deal succeeding, replied: "49 per cent."
Asked the same question, his German counterpart Frank-Walter Steinmeier put the odds at 51 per cent.
The complex, multi-sided civil war in Syria, raging since 2011, has drawn in most regional and global powers, caused the world's worst humanitarian emergency and attracted recruits to Islamist militancy from around the world.
Assad, backed on the ground by allied combatants and Hezbollah in addition to big power ally Russia, is showing no appetite for a negotiated ceasefire.
He declared this week that the government's goal was to recapture all of Syria, though he said this could take time.
The US government said Assad was "deluded" if he thought there was a military solution to the conflict.
Syrian state television announced the army and allied militia had on Saturday captured the village of Al Tamura overlooking rebel terrain northwest of Aleppo.
The Syrian Observatory for Human Rights reported advances in the same area, adding that Russian jets had hit three rebel-held towns near the Turkish border.
Government offensives around Aleppo have sent tens of thousands of people fleeing towards the Turkish border.
Speaking at the same conference, French Prime Minister Manuel Valls called on Russia to stop bombing civilians in Syria, saying this was crucial to achieving peace there.
"France respects Russia and its interests...But we know that to find the path to peace again, the Russian bombing of civilians has to stop," Valls said.
Russian Prime Minister Medvedev said that was simply not true.
"There is no evidence of our bombing civilians, even though everyone is accusing us of this," he said."Russia is not trying to achieve some secret goals in Syria.
We are simply trying to protect our national interests," he said, adding that Moscow wanted to prevent extremist militants getting to Russia.
Russia also has a major air base and large naval installation on Syria's Mediterranean coast.
US Secretary of State John Kerry, however, accused Russia of dropping so-called "dumb bombs" in Syria that do not have a precise target, saying this has led to the killing of civilians.
"To date, the vast majority of Russia's attacks have been against legitimate opposition groups.
To adhere to the (ceasefire) agreement it made, Russia's targeting must change," Kerry told the Munich conference.
Two Syrian rebel commanders told Reuters on Friday insurgents had been sent "excellent quantities" of Grad rockets with a range of 20 km (12 miles) by foreign backers in recent days to help confront the Russian-backed offensive in Aleppo.