More than 600 African migrants forced their way through the heavily fortified border fence separating the Spanish North African enclave of Ceuta from Morocco on Thursday, using circular saws, shears and mallets to cut through the wire.

Around 800 migrants tried to push through the barrier at dawn, the Interior Ministry said in a statement, deterring police from intervening by hurling plastic bottles of excrement, quick lime and using makeshift flame throwers.

Migration has become a political issue in Spain since Socialist Prime Minister Pedro Sanchez took office in June and shortly thereafter agreed to receive more than 600 migrants aboard a charity-run ship rejected by Italy and Malta.