At least five civilians were killed -- and dozens more injured -- by a twin bomb attack that rocked Syria's northwestern city of Idlib on Thursday, according to the White Helmets civil-defense agency.

Mustafa Haj Youssef, the White Helmets' director in Idlib, told Anadolu Agency that a car-bomb had exploded near the city's western entrance.

Shortly afterward, Haj Youssef said, a bomb-laden motorcycle exploded in the same area.

Thirty-five people were injured in the blast, many of them seriously, while a number of nearby buildings were severely damaged, he added.

There has as yet been no claim of responsibility for the deadly attack.