Syrian President Bashar al-Assad has said in an interview with Russian media he would only quit power if the Syrian people wanted him to and not under pressure from the West.

Western powers and much of the Syrian opposition say it is not conceivable for Mr Assad to lead a post-war Syria.

Mr Assad said Iran was supporting his government "politically, economically and militarily" but denied Iranian ground forces had been sent to help his armed forces.

His comments came as Russia increases its presence in Syria, a move which has caused concern in the US.

On his own position, Mr Assad said: "As for the president, he comes to power with the people's assent through elections, and if he leaves, he leaves if the people demand it, not because of the judgment of the US, the UN Security Council, the Geneva Conference or the Geneva Communique.

"If the people want him to stay the president stays. In the opposite case, he should swiftly step down."

The help of Iran, which had supplied military technology, had been crucial in fighting against terrorism in Syria, he said.

Mr Assad said there was no coordination between his government and the US in tackling the likes of Islamic Sate (IS), even indirectly, apparently backing away from comments earlier this year suggesting there had been some contact.

"There's not a single coordination or contact between the Syrian government and the US government or between the Syrian army and the US army.. Not even any third party including the Iraqis," he said.

He played down proposals for a peace initiative that Assad ally Iran has said it presented to Syrian officials.

"There is currently no Iranian initiative, but rather there are ideas, or principles, for an Iranian initiative which are based principally on the subject of Syria's sovereignty ... and are based on fighting terrorism," he said.

Meanwhile, France confirmed its fighter jets will start bombing IS targets in Syria in the coming weeks, despite growing doubts over whether the US-led air campaign against extremists in the region is working.

Opposition conservative policy-makers argued in Paris this week against joining the airstrikes, saying it would not change much on the ground.

But defence minister Jean-Yves Le Drian said French strikes would go forward "as soon as we have well-identified targets".

French planes have been striking Iraq but have so far stayed away from Syria, amid fears that it could strengthen Mr Assad.

Mr Le Drian said the French position had changed because of growing IS presence in Syria in recent months.

In another development, it emerged Israeli Prime Minister Benjamin Netanyahu will visit Russia next week for talks with President Vladimir Putin on the expanding Russian military presence in Syria.

An official in Mr Netanyahu's office said: "The prime minister will present the threats to Israel emanating from the increased flow of advanced weaponry to the Syrian arena and from the transfer of lethal weaponry to Hezbollah and other terrorist groups."