MOSCOW - Russia on Tuesday bombed targets linked to the Islamic State (IS) group in Syria near the historic city of Palmyra, killing "a great number" of personnel, the defence ministry said.

Six Tupolev bombers flew out from a base in Russia on Tuesday morning and "made a concentrated strike with fragmentation bombs on (IS) facilities" east of Palmyra and the towns of Sukhna and Arak, it said on Facebook.

Russia gave advance warning to the US-led coalition, which is conducting a separate bombing campaign in the war-torn country, the ministry said.

The IS were forced out of Palmyra by Syrian regime forces in March, but Arak and Sukhna, both seized in the spring of 2015, remain in the rebels' hands.

Arak, located 35 kilometres (21 miles) east of Palmyra, is a small town that has strategic importance because of a nearby oil field, while Sukhna, 70 km northeast of Palmyra, is an IS bastion.

Russia said its strikes targeted sites that were "recently detected and confirmed through several intelligence channels."

The raids killed "a great number of personnel" and destroyed a field camp as well as three ammunition depots, three tanks and a dozen other vehicles, Moscow said. Russian Foreign Minister Sergei Lavrov on Tuesday lambasted the UN envoy for Syria for failing to restart peace talks aimed at ending the brutal five-year conflict.

"We are concerned over the fact that the representative of the UN Secretary General (Staffan de Mistura) is shunning his duties and not convening the next round of inter-Syrian talks," Lavrov said at a press conference in the Azerbaijani capital Baku.

The UN-backed talks, aimed at ending a war that has left more than 280,000 people dead and driven millions from their homes, are in theory set to resume this month. But de Mistura has said that he wants guarantees of progress before restarting the process.

On Monday, de Mistura said a "crucial moment" had been reached in attempts to broker a political settlement, adding that "the key lies in a possible agreement between Russia and the United States". Lavrov said Tuesday this approach was "wrong".

"Syrians themselves must decide the fate of their country," he said. "External players, including Russia and the US, can of course continue influencing them."

US Secretary of State John Kerry is set to visit Moscow this week to seek common ground on how to deal with the ongoing bloodshed in Syria.

Meanwhile, hundreds of thousands of civilians in rebel-held areas of Aleppo risk starvation, the head of Syria's main opposition coalition said on Tuesday, accusing Damascus of trying to besiege the city into submission.

Aleppo, once Syria's economic powerhouse, has been ravaged by the conflict that began in March 2011 and has killed more than 280,000 people.

Anas al-Abdeh, the head of the Istanbul-based opposition National Coalition, complained allies of President Bashar al-Assad were showing greater commitment than the rebels' backers in the West.

This lack of "political will" was endangering the shaky peace process based around stop-start talks in Geneva to create a peaceful transition after over five years of civil war.

Assad's regime was seeking to completely control Aleppo's Castello Road - the rebels' last lifeline into the northern city - and impose a blanket siege, he told AFP in an interview.

"We are quite worried that if the Castello route is totally cut off, more than 300,000 civilians will starve and be under huge pressure," he said at the coalition's headquarters in Istanbul.

"Most of the humanitarian supplies are coming through this route. The regime is trying its best to besiege the city."

Rebels had on Monday launched a fierce offensive to reopen the Castello Road after it was severed by regime forces.

Abdeh said Russian air power was assisting the Syrian regime while Assad's other ally Iran was "basically managing, controlling, overseeing the military operation in Aleppo" on the ground.

He said Assad, Iran and Russia were working to create a "new military reality" in Syria that would then enable them to impose a political solution.

Aleppo has been divided between government forces in the west and rebels in the east since mid-2012 and is a key battleground.

Civilians have already reported shortages of food and fuel in the city's east, with local market stalls sparsely stocked and prices rising.

The United Nations says nearly 600,000 Syrians live in besieged areas of the country, most surrounded by government forces, although rebels also use the tactic.

"The friends of the regime are committing everything they have to help the regime. While our friends are not as committed in this regard," Abdeh said.

"I do not see a real political will in the international community to reach a political solution in Syria."

He said this could doom the Geneva-based peace process to find a political settlement, which has been deadlocked since late April when the last round ended.

"Without political will, what is happening in Geneva is just a PR exercise, nothing more than that.

"The current environment is not conducive to a successful process in Geneva."