BEIRUT (AP) — A resident and an opposition monitoring group say an explosion has rocked a camp for displaced Syrians on the border with Jordan, killing at least four.

Badr Abu Sultan, a resident of the Rukban camp, says a suspected car bomb in a local market caused the powerful explosion Saturday. Abu Sultan said two men, a woman and a child were killed and at least 12 were wounded.

The Britain-based Syrian Observatory for Human Rights also reported a suspected car bomb killed four.

The camp houses a local militia targeted in the past by rival factions in Syria's war.

Jordan has been on edge since a car bomb attack last year launched from Rukban killed seven Jordanian border guards. Jordan then sealed the border, cutting off aid to 75,000 Syrians there.