ALEPPO, Syria

At least six civilians were killed and dozens were injured Friday in airstrikes carried out by Russian warplanes in Aleppo, Syrian security sources said.

The sources added that the airstrikes, which targeted Azaz district, caused heavy damage to the hospitals’ buildings. One of the medical facilities is believed to be a children’s hospital.

Russian airstrikes have killed more than 250 civilians this week alone across Syria.

According to a report released earlier this month by Amnesty International, Russian airstrikes in Syria have killed “hundreds” of Syrian civilians over the last three months.

The report also suggests that the Russian authorities were attempting to cover up the mounting civilian death toll.

The report provides evidence that shows that the Russian military has used unguided bombs in densely populated civilian areas, along with internationally banned “cluster” munitions.

Amnesty International said that the airstrikes had caused massive destruction to residential areas -- striking homes, mosques, markets and medical facilities -- in violation of international humanitarian law.  

Russia began air operations in Syria on Sept. 30 with the aim of supporting the embattled regime of Syrian President Bashar al-Assad.

While the Kremlin says the airstrikes target the Daesh militant group, some members of the western NATO alliance believe Russia is targeting groups opposed to Assad, including some that enjoy U.S. and Turkish support.  

At least 250,000 people have been killed since the Syria conflict began in 2011, according to UN figures.