Leaders of the Free Syrian Army (FSA) have announced that they captured 13 suspected members of Lebanon’s Hezbollah militia around the Syrian city of Homs, and threatened to launch full scale attacks against the Lebanese capital city of Beirut if Hezbollah doesn’t withdraw entirely from the region.

The FSA statement said that Hezbollah is “deeply involved” in the ongoing civil war, and suggested that it was up to the field commanders whether to keep the captives or just execute them.

It is the second time this month that Hezbollah has come up in ongoing fighting, after the FSA reported that it killed a Hezbollah commander, Ali Hussein Nassif, in a bombing attack in Homs.

Hezbollah MP Kamel Rifai denied the FSA allegations of involvement in the civil war, saying that Hezbollah’s charter forbids them from participating in battles with anybody except for Israel, whose invasion of southern Lebanon was the impetus for their founding.