NICOSIA— Authorities in Cyprus have in the last two years prevented 18 foreign nationals from heading to Syria and possibly joining the Islamic State Group through the ethnically divided island’s breakaway Turkish Cypriot north, an official said Tuesday.

The Cypriot official, who spoke on condition of anonymity because he’s not authorized to publicly discuss security matters, said another 15 individuals were able to slip through. He said that all 33 cases have arisen since early 2014 and that the “vast majority” of those people were “European citizens of Islamic origin.”

Of the 18 who were stopped, the official said eight were British, seven French, two Swedes and a woman from the Netherlands. The individuals who slipped through included eight Britons, five Australians and two Finns.

Cyprus‘ eastern-most coast is less than 100 miles (160 kilometers) from Syria where the Islamic State group is fighting other rebel groups and President Bashar Assad’s forces. The island has been divided since 1974 when Turkey invaded in the wake of a coup by supporters aiming at union with Greece.

Seven checkpoints permitting people to cross between the internationally recognized south to the breakaway north have been in operation since 2003.

Cyprus has stepped up security at the checkpoints amid concerns that Europeans and other third-country nationals could travel to the European Union member country, cross northwards and then head to Syria from there via Turkey — the only country with direct air and sea links to the Turkish Cypriot north.

British Foreign Minister Philip Hammond said last July that Britain is “keen to work” with Cyprus to counter the threat posed by “foreign fighters going to Syria, Iraq and elsewhere.”

Britain is launching air strikes against Islamic State Group targets in Syria and Iraq from an air base it has retained on Cyprus since the island gained independence from British colonial rule in 1960.

MENELAOS HADJICOSTIS, Associated Press