Russia's campaign of air strikes in Syria is set to last between three to four months and bombardments will intensify, a senior Russian lawmaker said on 2 October. The announcement comes a day after the US accused Russia of launching "indiscriminate military operations against the Syrian opposition".

"There is always a risk of getting bogged down but, in Moscow, they're talking about three to four months of operations," Alexei Pushkov, the head of the lower house of the Russian parliament's foreign affairs committee, told French radio station, Europe 1. He added that more than 2,500 air strikes in Syria by a US-led coalition against Islamic State (Isis) had yielded no results and was a pretence.

"I think it's the intensity that is important. The US-led coalition has pretended to bomb Daesh (IS) for a year, without results," Pushkov said. "If you do it in a more efficient way, I think you'll see results," he added.

Russian President Vladimir Putin is set to meet with his French counterpart in Paris on 2 October to discuss peace efforts in Ukraine, but the agenda is expected to be dwarfed by the Kremlin's recent entry into the Syria conflict. Like the US, France is hitting IS with air strikes, but there is growing concern that Russian targets are going beyond terrorist groups and are instead targeting anti-Assad groups, including the US-backed Free Syrian Army (FSA).

Speaking at the UN in New York on 1 October, Russian Foreign Minister Sergei Lavrov said the country would also attack other terrorist groups, including al-Nusra Front (an al-Qaeda affiliate) and "other terrorist groups recognised by the UN Security Council or Russian law".

"If it looks like a terrorist, if it acts like a terrorist, if it walks like a terrorist, if it fights like a terrorist, it's a terrorist, right?" Lavrov responded when asked to define what constitutes "other terrorist groups".

Pushkov denied allegations that Russia was bombing Assad's opponents, saying: "The main target are the Daesh groups situated closest to Damascus. We need to eliminate this group or at least neutralise it and afterwards we'll see what Syria's future is."

Russia has also carried out air strikes on Raqqa, an IS stronghold and de facto capital, the country's defence ministry said on 2 October. "On 1 October, Su-34 planes carried out strikes on an IS training camp... and on a camouflaged command post... south west of the town of Raqqa," the ministry said. "As a result of the strikes, the IS command point was put out of action. The infrastructure used to train terrorists was completely destroyed."