PRESIDENT Bashar al-Assad has claimed a military campaign by Russia, Syria and its allies must succeed "or else the whole region will be destroyed".

Mr Assad said yesterday the coalition will decide the fate of the Middle East and that a year of US-led air strikes against Islamic State militants had only helped the spread of terrorism.

In an interview with Iranian television broadcast yesterday, President Assad said if Syria, Russia, Iran and Iraq unite in battling terrorism their efforts would yield practical results.

He was speaking days after Russian jets, based in western Syria, launched air strikes against targets Moscow has identified as Islamic State (IS) bases, but which Mr Assad's opponents say disproportionately hit rival, foreign-backed insurgents.

"The chances of this alliance's success are big, not small," said the president, adding that failure would mean "we face the destruction of the whole region".

He said a campaign of Western and Arab air strikes against Islamic State targets in Iraq and Syria had been counterproductive and terrorism had spread both in terms of territory and new recruits.

Syria's conflict grew out of protests against Assad's rule in early 2011, which were put down by force and then turned violent, drawing in regional opponents and supporters of the Syrian leader.

Efforts to find a political solution to the civil war have so far proven fruitless, with most rebel fighters demanding Mr Assad's departure as a precondition for talks. Western states also say Assad must step aside, though most have softened their stance to say he could play some role in a transition period.

Mr Assad said it was not for outside powers to decide Syria's fate. "Discussion of the political system or officials in Syria is an internal Syrian affair," the Syrian presidency's Twitter feed quoted him as saying in the interview.

Mr Assad spoke as Russia carried out more air strikes in Syria which it said targeted so-called Islamic State (IS) positions.

Syrian activists have repeatedly claimed the raids appear to be focused on other rebel groups.

Mr Assad's international opponents say a negotiated solution to Syria's four-year-old civil war must involve the president stepping down, although some Western nations, including the UK, have now conceded that he could remain during a transitional period.

But Mr Assad insisted: "Discussion about the political system or officials in Syria is an internal Syrian affair."

Russia's defence ministry said yesterday that its aircraft had bombed 10 IS targets in Syria over the past 24 hours - including command posts, a training camp, ammunition stores and a workshop making explosive devices including suicide belts.

It also warned its air campaign, which began on Wednesday, was being expanded.

"As a result of our air strikes on Isil [IS] targets, we have managed to disrupt their control system, the terrorist organisation's supply lines, and also caused significant damage to the infrastructure used to prepare acts of terror," the ministry added.

Syrian activists said Russian strikes in central Homs province had killed at least two children and a shepherd, and wounded a further 15 people.

The Syrian authorities have reportedly detained a prominent opposition figure, days after he criticised the Russian air strikes.

Munzer Khaddam, spokesman for the National Co-ordination Committee for Democratic Change, was held at a checkpoint near the capital Damascus, an official from his group told AFP news agency.

Both the UK and Turkey have condemned Russia's military intervention.

Turkish President Recep Tayyip Erdogan described it as a grave mistake that would further isolate Moscow.

In London, David Cameron said Russia's actions would lead to further radicalisation and terrorism.

"Tragically, what has happened is that most of the Russian air strikes, as far as we have been able to see so far, have been in parts of Syria not controlled by Isil (IS) but controlled by other opponents to the regime.

"So what is happening is that they are backing the butcher Assad, which is a terrible mistake for them and for the world; it's going to make the region more unstable, it will lead to further radicalisation and increased terrorism."