"Yes, they [the US] have apologized" for the airstrike on Syrian troops, which killed dozens, Russian Foreign Minister Sergei Lavrov said during an interview with the TV channel Rossiya-1, as reported by Sputnik.

On September 16, airplanes from the US-led coalition against ISIS hit Syrian army positions at a military airport near Deir ez-Zor, which is besieged by the terrorist group.

Lavrov also referred to a recent attack on UN humanitarian convoy in Syria, and stressed that, for objective probe in incident, it is necessary to find and examine ammunition used to hit the convoy.

In order for the investigation of the incident with the humanitarian convoy in Syria to be considered objective, the ammunition used on it must be shown, Lavrov said.

"Now it is necessary to conduct an investigation. Probably the easiest way and the very first step that should be made is to [examine] the ammunition that was used [during the attack] on the convoy," Lavrov went on to say.

"First there appeared information claiming it was hit with artillery, and then this information disappeared. After that people spoke about helicopters; I think everyone would be able to understand what happened if we were able to see the ammunition."

A UN-Syrian Arab Red Crescent convoy carrying humanitarian aid for Syria's Aleppo province was attacked late on Monday, according to the International Federation of Red Cross and Red Crescent Societies (IFRC).

As a result, 18 of 31 trucks were destroyed and at least 21 individuals were killed. Humanitarian convoys expected to travel on Castello road to Syria's Aleppo are threatened by armed groups controlling eastern Aleppo, Lavrov said.

"The Syrian government has confirmed its readiness to cooperate on the issue. But the same day, those who control eastern Aleppo and call themselves 8216;the local council' said that if the convoy went via Castello road they would attack it," Lavrov noted.

Millions of Syrian people remain in urgent need of humanitarian aid that cannot be delivered due to continuous fighting.

According to the United Nations, around two million people need humanitarian assistance in the Syrian city of Aleppo, which has seen intense fighting in the past several weeks.

Several western officials, including the ones from the White House, have blamed the attack on Russia and Syria. However, the Russian authorities have refuted the allegations.