Only a third of Russian airstrikes in Syria are targeting ISIL and its imprecise attacks are forcing the population to flee, fuelling Europe's refugee crisis, Reuters quoted an unnamed senior US official as saying on Saturday.

Of the 5,000 airstrikes carried out by Russia since it began its air campaign in Syria on September 30, about 70 percent hit militants fighting against the government of Syrian President Bashar al-Assad, rather than supporting the efforts of the US-led coalition, the official told reporters in Brussels.

Russia launched its airstrikes against Takfiri terrorists in Syria at the request of the Damascus government. Moscow says its air raids are meant to weaken Daesh and other terrorist groups that are wreaking havoc in the Arab country.

But the US official who spoke on condition of anonymity said, "We are not convinced of what the Russian intentions are."

"For a while, very few strikes were going against ISIL and after a lot of public condemnation they turned a number of strikes against ISIL."

The official said Russia used fewer precision-guided munitions than the United States and its allies.

"The Russian strikes that are not precise cause me great concern because I think there is an indirect correlation to the refugee flow," the official said. "It is not just the pressure it is putting on NATO and the EU, it is also the humanitarian cost."

Amnesty International last month accused Moscow of violating humanitarian law. It estimated that at least 200 civilians were killed by Russian airstrikes between September 30 and November 29, which Russia denies.

Russia's Defense Ministry has repeatedly denied targeting civilians, saying it takes great care to avoid bombing residential areas.

Since September 2014, the US along with some of its allies has been conducting air raids against what are said to be the Daesh terrorists inside Syria without any authorization from Damascus or a UN mandate. The air assaults in Syria are an extension of the US-led aerial campaign against purported Daesh positions in Iraq, which started in August 2014.

Reports say US-led strikes have also killed scores of civilians in Syria ever since.

Syria has been grappling with a foreign-backed militancy since the early 2011. The violence has reportedly driven 4.4 million Syrians into neighboring states from where many are trying to reach Europe, Press TV reported.

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