BEIRUT - Suspected Russian air strikes killed at least 54 civilians in rebel- and jihadist-held areas of Syria in the past 24 hours, a monitoring group said Thursday.

The Syrian Observatory for Human Rights said strikes on Wednesday had killed 29 civilians, including nine women and three children, in villages controlled by the Islamic State group in the eastern Deir Ezzor province and its provincial capital of the same name.

The strikes killed another 15 civilians, including five young brothers, in and around the city of Al-Bab, an IS bastion in the northern province of Aleppo, the Observatory said.

Ten more civilians, including seven children, were killed in Russian strikes in Ghanto, a town held by Islamist rebels in the central province of Homs, it said.

The Britain-based monitor relies on a network of activists on the ground and says it distinguishes between Syrian, Russian and US-led coalition aircraft based on flight patterns, as well as the type of planes and ordnance used.

Russia launched air strikes in Syria in September in support of President Bashar al-Assad’s regime, a key ally. The US-led coalition has been carrying out strikes against IS targets in Syria and Iraq since the summer of 2014.

Russian backing has helped Assad’s forces make significant advances in recent months and the Observatory said Thursday that regime troops had moved to within eight kilometres (five miles) of Al-Bab.

Meanwhile, Syrian opposition members met for a third day Thursday to decide whether to attend UN peace talks, with less than 24 hours before the negotiations were due to begin in Geneva.

Opposition sources said it appeared increasingly unlikely the talks would open in the Swiss city on Friday as planned. The Saudi-backed High Negotiations Committee - formed last month in an effort to unite Syria’s fractious opposition - said it was waiting for answers from the United Nations before agreeing to attend the talks.

Western diplomats have piled pressure on the opposition to participate in the negotiations, part of the biggest push yet to resolve Syria’s nearly five-year civil war.

But after two days of meeting in the Saudi capital the Committee, which was formed to lead negotiations and insists it alone must represent the opposition, had yet to agree to participate.

The Committee has asked for “clarifications” after the UN issued invitations to other opposition figures and wants assurances from the international community that it will move to end regime attacks on civilians and allow humanitarian aid.

Salem al-Meslet, a Committee spokesman, said it was waiting for an answer from UN Secretary General Ban Ki-moon on the application of a Security Council resolution adopted in December that endorsed a roadmap for peace.

He said UN Syria envoy Staffan de Mistura had already assured the opposition that two of the resolution’s articles - calling for immediate access for humanitarian aid and an end to attacks on civilians - were non-negotiable.

Security Council members “must take their responsiblities and commit to applying resolution 2254. We are waiting for an answer,” Meslet said.

“We are serious about participating in the negotiations. The ones who are hindering the start (of talks) are those who are bombing and starving civilians.”

France-based Middle East analyst Agnes Levallois said the opposition was growing increasingly frustrated that the question of President Bashar al-Assad’s fate was being put off.

“Assad is feeling stronger and stronger so is being inflexible. He wants to be sure there are no longer talks on his future so is putting forward the humanitarian issue,” she said.

Haytham Manna, a longstanding opposition figure who is co-chair of the political wing of a Kurdish-Arab alliance, told AFP in Geneva he did not expect talks to begin until Monday.

“There are a lot of issues that were not resolved,” he said, pointing to the dispute over invitations to the opposition.

A source close to the government in Damascus said its delegation, headed by envoy to the UN Bashar al-Jaafari, would be arriving on Friday as planned.

The talks are part of a UN-backed plan, agreed by top diplomats last year in Vienna, that envisages negotiations followed by a transitional government, a new constitution, and elections within 18 months.

The roadmap is the most ambitious plan yet to end the conflict which has killed more than 260,000 people and forced millions from their homes.

Officials have said the talks, only the second dialogue between Syrians since the start of the conflict, would run over six months, with the first round expected to last between two and three weeks.

- ‘Russian strikes’ kill 54 -

Russia said on Thursday it wanted another meeting of world powers on Syria in Munich on February 11, when the first round of the Geneva talks could still be taking place.

De Mistura’s office said on Tuesday it had issued invitations to the talks, but refused to say who had been invited.

The Committee, which has named Mohammed Alloush of the Islamist rebel group Army of Islam as its chief negotiator, confirmed it had received an invitation, but so did several other opposition figures not belonging to the body.

It was unclear whether the others had been invited as official delegates or as observers.

Russia, a key Assad ally, has called for broader opposition representation while Ankara has warned against any participation of Kurdish forces it says are linked to Turkey’s outlawed Kurdistan Workers’ Party (PKK).

There have been no suggestions that jihadist movements, including the Islamic State group which has seized control of large parts of Syria and neighbouring Iraq, should be invited.

The push for talks comes as Syrian forces have been advancing against rebels in various parts of the country, thanks in large part to Russian air strikes launched in September.

Critics have accused Moscow of killing hundreds of civilians in the strikes and on Thursday a monitor said at least 54 civilians had died in suspected Russian air raids in parts of northern and eastern Syria under IS control.