A car bomb has exploded at a key border crossing with Turkey. Syrian rebels said the bomb exploded on the Syrian side of the Bab al-Hawa crossing point on Tuesday, killing at least 15 people.

Activist group the Syrian Observatory for Human Rights also confirmed the attack, saying it hit the main gateway to the crossing. Activists said Bab al-Hawa has been largely under rebel control since last September.

Tuesday's attack wasn't the first there. In February, a car bomb exploded at the border post, killing 14 people. And in May, 43 people were killed when two car bombs exploded on the Turkish side.