Governor"s Office of Gaziantep, a province on the Syrian border, said in a statement on Tuesday that citizens from Kosovo, Syria, Switzerland, Russia and Tajikistan were detained while trying to "illegally cross into Syria." The statement said the Turkish security services suspect that the foreign citizens were headed to conflict zones in Syria to fight.

Thousands of foreigners from different countries have joined the ranks of radical groups such as Islamic State in Syria and Levant (ISIL), many of them crossing through Turkey.

Turkey has stepped up border security, regularly releasing details of would-be fighters it has detained, after criticism it had not done enough to stem the flow of foreign fighters through the region.