Two children were among at least seven civilians killed in air strikes carried out by Russian warplanes in Syria's northwestern province of Idlib, a monitoring group said Friday, citing witnesses.

"Four civilians, including a child and a woman, were killed in raids conducted by Russian military aircraft," said the Syrian Observatory for Human Rights.

Russian warplanes unleashed a new wave of strikes against opponents of Syrian President Bashar Assad Thursday, as Moscow and Washington sought ways to avoid confrontation between their forces.

It was the second straight day of Russian raids in Syria, where Moscow has launched its first military engagement outside the former Soviet Union since the occupation of Afghanistan in 1979.

The Pentagon will launch talks with the Russian military Thursday to discuss ways to avoid mishaps between planes from the U.S.-led coalition and Moscow, a defense official said.

The United States has repeatedly stressed the urgent need for Russia to communicate with it about when and where it plans to fly its fighter jets and bombers.

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.

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.

Kiev said on Wednesday it had struck an initial agreement with pro-Russian insurgents to withdraw smaller weapons from the buffer zone splitting eastern rebel lands from the rest of Ukraine.

International monitors said the two sides' February commitment to pull back heavy weapons from the 500-kilometer (300-mile) line separating the forces was only observed laxly and led to more than 1,000 deaths.

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.

Ukrainian President Petro Poroshenko used his speech at the U.N. General Assembly on Tuesday to rail against Russian aggression, urging the world not to believe "conciliatory" statements from his counterpart Vladimir Putin.

The Russian leader called Monday for a broad U.N.-backed coalition to fight the Islamic State group as he seeks to muscle his way back onto the world stage after months of isolation over Ukraine.