The amateur video below was recorded shortly after an air strike hit a fuel station in the town of Ain Eissa in Syria's northern province of al-Riqqa on Thursday.

At least 54 people were killed, activists said.

Al Jazeera's Andrew Simmons, reporting from Antakya in neighbouring Turkey on Friday, said there is "no doubt that it was a targeted attack on an area being used by civilians".

"The petrol station was crowded out with vehicles. It was the only petrol station, activists say, in the entire region that was open to the public," he said.

"It was supposed to be an improvised device; we are hearing from unconfirmed reports [it was] a barrel bomb. These sorts of things have been described in Aleppo before. It was devastating.

"The casualties number in the dozens, and now we are getting unconfirmed reports that the death toll has reached 60."