President Vladimir Putin on Wednesday said Syria's embattled leader Bashar Assad must be ready for compromise with the opposition as Russia launched its first air strikes in the war-torn country.

"We are counting on his active and flexible position, his readiness for compromise for the sake of his country and his people," Putin said at a televised government meeting.

Russia's powerful Orthodox Church on Wednesday voiced support for Moscow's decision to carry out air strikes in Syria against the Islamic State group, calling it a "holy battle."

"The fight with terrorism is a holy battle and today our country is perhaps the most active force in the world fighting it," said the head of the Church's public affairs department, Vsevolod Chaplin, quoted by Interfax news agency.

At least 27 civilians were killed Wednesday and dozens more wounded in fierce regime bombardment of several residential areas in central Syria, a monitoring group said.

"Regime warplanes conducted raids on Rastan, Talbisseh, and Zaafarani in Homs province," said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.

Russia launched air strikes in war-torn Syria on Wednesday, its first military engagement outside the former Soviet Union since the occupation of Afghanistan in 1979.

Russian warplanes carried out strikes in several Syrian provinces along with regime aircraft as Vladimir Putin seeks to steal U.S. President Barack Obama's thunder by pushing a rival plan to defeat Islamic State militants in Syria.

France's first air strike on the Islamic State group in Syria killed at least 30 jihadists, including 12 child soldiers, a monitoring group said on Wednesday.

"The French air strike (on Sunday) on an IS training camp in eastern Syria killed at least 30 IS fighters including 12 from the 'Cubs of the Caliphate,'" said Rami Abdel Rahman of the Syrian Observatory for Human Rights.

A quarter of the more than 200,000 civilians killed in Syria's conflict since 2011 have been women and children, and the high rate of non-combatant deaths has likely fueled the refugee crisis, a study released Wednesday said.

The proportion and cause of these civilian deaths differed in government-held and rebel areas, said the study, published in the British Medical Journal.

The U.N. chief's Deputy Special Coordinator for Lebanon, Philippe Lazzarini, has lamented that the response of the international community to the needs of Syrian refugees in Lebanon and other countries is weak.

In an interview with An Nahar daily published on Wednesday, Lazzarini said: “The response does not meet the needs.”

France has launched an inquiry into Syrian President Bashar Assad's regime for alleged crimes against humanity, saying it was forced to act in the face of "systematic cruelty".

The announcement Wednesday came after world powers sparred at the United Nations over the embattled Syrian leader's fate.

Israeli Defense Minister Moshe Yaalon has warned that Israel will not tolerate advanced weapons reaching Hizbullah, which has fought alongside Syrian troops.

“Those who try to violate our sovereignty – we will strike them, and those who try to transfer advanced weapons to terror elements, with an emphasis on Hizbullah, we will strike them, and those who try to transfer chemical weapons to terror elements, we will strike them,” Yaalon said on Tuesday during a visit to Gaza-border communities.

Japanese Prime Minister Shinzo Abe committed $1.5 billion Tuesday to help refugees from Syria and Iraq, and to support peace building efforts in the wider Middle East to stem the crisis.

He made the announcement at the U.N. General Assembly while pressing for reforms that would allow Japan -- the second largest contributor to the U.N. budget -- to become a permanent member of the Security Council.