BEIRUT, Lebanon - An ammunition dump exploded in Lebanon near the Syrian border late Monday inside a base of a Syrian-backed Palestinian terror group, Lebanese security officials said.

There were no reported casualties in the explosion, the cause of which was unknown, the officials said on condition of anonymity citing security concerns.

The blast happened inside a mountain cave within the base of the Palestinian Popular Front for the Liberation of Palestine-General Command, located near the village of Qosaya, 50 kilometers east of Beirut, the officials added.

Lebanon's officials National News Agency said PFLP-GC members sealed off the area and prevented journalists from approaching the base, which is also off limits to Lebanese security forces under an arrangement they have with the Palestinian terror group.

The group is headed by Ahmed Jibril, who has maintained bases in Lebanon since thousands of Syrian troops completed their pullout from this country in April under intense US-led pressure and following the February 14 assassination of ex-Lebanese premier Rafik Hariri.

Groups like the PFLP-GC have long been viewed as Syrian political cards to improve Damascus' negotiation position with Israel. The group receives arms from Syria and is one of the terror groups based in Damascus which the United States insists Syria should expel. (AP)