PARIS - France called on the United Nations to take swift moves to establish cessation of hostilities in Syrian city of Aleppo, which has been under military escalation, French Foreign Minister Jean-Marc Ayrault said on Tuesday.

"I call on the United Nations to use without delay all the mechanisms to establish the truth of what is happening in Aleppo so that the international community does not let these crimes remain unpunished," Ayrault stressed.

The French top diplomat said all the light must be shed on civilians' suffering including women and children execution and targeting of hospitals.

Aleppo, a major city and commercial hub in northern Syria, has been torn into two parts with western area controlled by Syrian army and eastern held by rebels since 2012.

In September, Syrian army backed by Russian air force intensified its airstrikes on rebel positions in Aleppo and recaptured main districts of the city.

The offensive has been widely seen as a turning point of the five-year civil war.

According to media reports, forces loyal to Syrian President Bashar al-Assad on Tuesday are taking control over Aleppo after rebels' retreat.