The Taliban have denied they held talks with Russia about countering the spread of Islamic State in Afghanistan, and dismissed the influence of the jihadist group in the country.

The insurgents were responding to a statement Wednesday by senior Russian diplomat Zamir Kabulov, who said his country was exchanging information with the Taliban about the group.

One of three suspected rebels killed in fighting in the restive North Caucasus was trained by "terrorists" in a camp in Syria, Russian authorities said Thursday.

The trio were killed by special forces on Tuesday in the Kabardino-Balkaria region, near Georgia, close to a mountain village called Lechinkai, said a spokesman for the national anti-terror committee, quoted by the Interfax news agency.

Amnesty International said on Wednesday that nearly three months of Russian air raids in Syria have killed hundreds of civilians, many in targeted strikes that could constitute war crimes.

Some strikes "appear to have directly attacked civilians or civilian objects by striking residential areas with no evident military target and even medical facilities, resulting in deaths and injuries to civilians," Amnesty Middle East and North Africa director Philip Luther said in a statement.

Russia said Wednesday it had issued an international arrest warrant for top Kremlin critic Mikhail Khodorkovsky, as Moscow ramped up the pressure on a leading critic of President Vladimir Putin.

Earlier this month the Investigative Committee, which reports directly to Putin, charged the former oil tycoon in absentia with organizing the 1998 murder of a mayor in Siberia, a move supporters say is aimed at silencing the exiled Kremlin foe.

The Syrian Observatory for Human Rights said Tuesday that Russian air strikes have killed 2,132 people in Syria, a third of them civilians, since they began on September 30.

Of those killed, 598 were fighters from the Islamic State group and another 824 from al-Nusra Front, the Syrian affiliate of al-Qaida, and other rebel groups.

Russian investigators on Tuesday raided the apartments of employees of Kremlin critic Mikhail Khodorkovsky's Open Russia group, less than two weeks after Moscow charged the former tycoon with murder.

Members of the government's Investigative Committee searched the homes of Khodorkovsky's spokeswoman Kulle Pispanen and employees of his opposition group Open Russia.

Taiseer Hamash cradled his two-month old daughter Noor Sham in his arms as he stood by the entrance of the tarpaulin tent his family has called home in war-wracked Syria for over a year.

"She has never seen our old house," said the former factory worker, 29, who fled the fierce fighting in his home region of Aleppo.

French Defense Minister Jean-Yves Le Drian flew in to Moscow on Monday for a meeting with his Russian counterpart to request an increase in strikes against the Islamic State (IS) group in Syria.

Talks will also touch on how the two countries can share intelligence relating to the jihadist group, Le Drian told journalists before traveling to Russia.

Russia is not trying to bring back the USSR, President Vladimir Putin said in a documentary aired Sunday, but the problem is that "nobody wants to believe it".

Since the beginning of the Ukraine crisis, which saw pro-Russian leader Viktor Yanukovych ousted by pro-European demonstrators, Moscow has accused the West of using "the politics of containment" in a Cold War throwback.

Suspected Russian air strikes have killed 32 civilians, half of them women and children, in three areas in northern Syria, the Syrian Observatory for Human Rights said on Friday. 

Observatory head Rami Abdel Rahman said warplanes bombarded Raqa, the Islamic State group's de facto Syrian capital, as well as the towns of Azaz and Al-Bab in Aleppo province, on Thursday.