BEIRUT - Air strikes by Russian warplanes on the Islamic State-held Syrian city of Raqqa killed 42 people earlier this week, including 27 civilians, monitoring group the Syrian Observatory for Human Rights said on Friday.
Fifteen Islamic State fighters made up the remainder of the death toll, the Britain-based Observatory said, after a series of strikes on Tuesday that hit the group's Syrian stronghold.
The bombings add to a civilian death toll from Russian strikes, which the Syrian Network for Human Rights, another monitoring group, said on Monday stood at 254 people killed in just over a month. It was also a rare heavy Russian bombardment targeting Islamic State rather than other insurgent groups.
Russia's air force intervened in Syria's four-year civil war on Sept. 30 on the side of President Bashar al-Assad, launching a campaign it said targeted Islamic State. The United States says Russian raids have mostly hit other Syrian insurgents, including foreign-backed and more moderate groups.
The Russian intervention has marked a new phase in the war, intensifying fighting in the country's west and northwest between rebels and pro-government forces backed also by Iranian troops and Lebanese Hezbollah fighters.
Russian strikes have hit Islamic State-held areas further east, but have been mostly concentrated in the west.
Meanwhile, Saudi Foreign Minister Adel al-Jubeir has held talks in Oman, a traditional mediator in the region, on the conflicts in Syria and Yemen where Riyadh has taken sides.
Jubeir and his Omani counterpart Yussef bin Alawi reviewed "the situation in Syria and Yemen and means of strengthening cooperation" among the six Arab states in the Gulf, the Saudi foreign minister said late Thursday after their meeting in Muscat. He told Oman's ONA news agency that "the view is one" between Saudi Arabia and Oman on "all the matters discussed today".
Unlike its Gulf neighbours, Oman maintains good ties with Shiite Iran - a key backer of Syrian President Bashar al-Assad's regime and of Shiite Huthi rebels in Yemen.
It is also the region's only Arab monarchy not to have cut ties with Damascus.
Saudi Arabia has taken an active role, supplying arms to anti-Assad rebel groups and leading an Arab coalition battling rebels in Yemen.
Alawi, for his part, said the sultanate was "exerting diplomatic efforts to find a peaceful solution in Syria and Yemen".
Oman is seeking through "calm diplomacy... rapprochement among all parties to achieve long-lasting political solutions", Alawi, who met Assad in Damascus last month, told ONA.
He said Riyadh and Muscat had "shared goals" on regional conflicts and "agreed to look forward and break from the past concerning regional issues".
His visit to Damascus had been "necessary", Alawi said, adding that the meeting with Jubeir had been scheduled before his talks with Assad.
Oman's discreet diplomacy has contributed to several breakthroughs this year, including the release in August of a French hostage held in Yemen and Iran's nuclear deal with world powers in July.
The sultanate has also hosted closed-door meetings between Yemeni rebel leaders and US officials.