This image made from footage taken from Russian Defence Ministry official website on Friday shows an attack made from a fighter jet in Syria.
Beirut - Moscow undeterred by strong criticism from Western, Gulf powers and Turkey
Russian bombing raids on Syria entered their fourth day on Saturday, striking the Deash group's main stronghold after the Kremlin came under fire from the West for targeting moderate rebel groups.
A staunch backer of Syria's President Bashar Al Assad, Moscow began sorties over the country on Wednesday in what it said would be a prolonged aerial campaign against Daesh and other extremist groups.
But it has been accused by the United States and its allies of instead targeting mainly Western-backed opponents of Assad, with President Barack Obama warning that its strategy was a 'recipe for disaster'.
Moscow said on Saturday that its jets had destroyed a Daesh command post near the group's main Raqa stronghold as well as an underground bunker.
"Over the past 24 hours, SU-34 and SU-24M jets of the Russian airborne formation in Syria made more than 20 sorties over nine Daesh infrastructure facilities," the defence ministry said.
The Syrian Observatory for Human Rights said Russian strikes "hit Daesh positions west of Raqa overnight and explosions were heard in the city".
Raqa has acted as the extremist group's de facto Syrian 'capital' since 2013.
The Observatory, which relies on a network of sources on the ground for its information, said Russian jets had killed 12 militants in Raqa this week.
But raids ordered by Moscow have also hit areas controlled by moderate groups that are fighting Assad and even prompted a claim by US Senator John McCain that Russian jets had killed rebel soldiers trained and funded by the CIA.
Obama told reporters that Russia "doesn't distinguish between Daesh and a moderate opposition that wants to see Assad go.
"From their perspective, they're all terrorists. And that's a recipe for disaster."
Russia said its strikes this week had completely destroyed Daesh positions in northern Aleppo province, neighbouring Idlib province and in Hama in central Syria.
But several military sources and the Observatory said Russia had hit areas controlled by groups other than Daesh.
The Observatory also says Russian strikes have killed several civilians and wounded doctors in a raid on a hospital in Hama.
The Syrian conflict began as an uprising against Assad's rule in 2011 but has splintered into a multi-front civil war with government troops, moderate rebels, militants and Kurdish forces all vying for control.
More than 240,000 people have been killed in the conflict, with four million more forced to flee the country.
A US-led coalition has been bombing IS positions in Syria since September 2014 but the extremists have still managed to take ground, including the ancient desert city of Palmyra, a UN world heritage site.
Turkish President Recip Tayyip Erdogan, one of the fiercest critics of Assad, urged Russian President Vladimir Putin to reconsider his strategy in Syria.
"I will definitely speak to Putin. I will express my sadness over this matter," he told Al-Jazeera Arabic on Saturday.
"I want to understand why Russia is so interested in Syria," Erdogan said, adding he had 'received information' that 65 people had died so far in Russian bombing runs, without specifying the source of the toll.
The EU on Friday also called on Russia to concentrate its firepower on IS.
"The fight against Daesh must be directed against Daesh," said EU foreign affairs spokeswoman Catherine Ray.