Updated

Syrian activists and Turkish media say an explosives-laden vehicle has detonated near a field hospital just across the border from Turkey, causing casualties.

The Britain-based Syrian Observatory for Human Rights and Turkey's state-run Anadolu agency both reported the Sunday incident in the rebel-held northwestern Syrian town of Atmeh.

The Andalou agency said several people were killed and wounded.

The town of Atmeh hosts a sprawling camp for thousands of displaced Syrians. It wasn't immediately clear who operate the hospital, nor who may have carried out the bombing.

A Feb. 20 car bomb targeted the Bab al-Salama border crossing in another part of northern Syria. The region is contested between rebel brigades and an al-Qaida breakaway group, the Islamic State in Iraq and the Levant.