A coalition between Syria, Russia, Iran and Iraq must succeed “or else the whole region will be destroyed”, Syrian President Bashar al-Assad says.

Assad also criticised the US-led coalition and its air strikes in Syria and Iraq as counterproductive, saying that terrorism had only spread.

Meanwhile, Russia has carried out more air strikes in Syria it says targeted so-called Islamic State (IS) positions.

Syrian activists say the raids appear to have focused on other rebel groups.

In an interview with Iranian state television, reported by the Syrian presidency Twitter feed, President Assad said Syria, Russia, Iran and Iraq were united in battling terrorism and would achieve “practical results”, unlike the US-led coalition.

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 now say he could remain during a transitional period.

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

Russia’s defence ministry said on Sunday 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 said 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.

Turkey and Britain have condemned Russia’s military intervention in support of President Assad.