Russian jets have unleashed a new wave of strikes against opponents of Syrian President Bashar al-Assad, as Moscow and Washington discussed how to keep out of each other's way.
It was the second day of Russian raids in Syria, and came on the eve of talks between President Vladimir Putin and his French counterpart Francois Hollande in Paris.
Russia's defence ministry said its air force struck five Islamic State (IS) group targets, although Western officials expressed concern that they are hitting opposition rebel fighters.
"We have prevented IS fighters from re-establishing a command post in the Hama province that had been destroyed," spokesman Igor Konashenkov said.
The ministry said an IS training camp and command post in northwest Idlib province were also hit.
Putin rejected allegations that civilians had been killed in Russian raids, dubbing the reports "information warfare".
The air strikes came as Russia presented a draft resolution to the UN Security Council that would call for consent from Damascus for attacks against the Islamic State group in Syria.
Washington had previously blocked a similar resolution, and no date has been set for a vote on this one.
The Syrian conflict, which began as protests against Assad's regime in 2011, has escalated into a multi-faceted war that has drawn thousands of jihadists from overseas.
Moscow, a key Assad ally, had earlier said its raids destroyed a "terrorist" headquarters, a weapons warehouse, a command centre and a car bomb factory.
But a Syrian security source said the strikes targeted Islamist rebels, the Army of Conquest, which includes Al-Qaeda's Syria affiliate the Al-Nusra Front and which fiercely opposes IS.
Hollande said, before his talks with Putin, that air strikes in Syria should target IS, not other groups.
He said it was essential to ensure that "the strikes, regardless of who is carrying them out, target Daesh and not other groups".
Turkish Foreign Minister Feridun Sinirlioglu said he felt "serious concern over the information that Russia's air strikes targeted opposition positions instead of Daesh".
Sinirlioglu was to meet US Secretary of State John Kerry later Friday (local time).
Russian Foreign Minister Sergei Lavrov has rejected the accusations, saying Moscow saw "eye-to-eye" with the US on striking IS and Al-Nusra.
"If it acts like a terrorist, if it walks like a terrorist, if it fights like a terrorist, it's a terrorist, right?" he asked.
Asked if it was true that Russia and the United States were on the same page, Kerry said: "Well, in concept, but we are not yet where we need to be."
After complaints by the US that Russia gave just an hour's notice of Wednesday's attacks, the two sides held so-called de-confliction talks by teleconference, US officials said.
"We made crystal clear that at a minimum the priority here should be the safe operation of the aircrews over Syria," Pentagon press secretary Peter Cook said.