A total of 680 undocumented migrants have been held in Turkey since Monday, according to security sources and Turkish military on Tuesday.

In a statement posted on its official website, the Turkish General Staff said 629 people were held when they attempted to cross the Turkish borders through illegal means.

Out of the 629 migrants, 404 of them attempted to cross into Turkey from Syria, 51 made attempts from Greece, 173 others attempted to cross into Greece and another migrant tried to cross into Turkey from Iran.

Meanwhile, coastguards detained 51 foreign nationals in simultaneous operations when they stopped inflatable boats, which were carrying the undocumented migrants, in the Çeşme and Dikili districts of western Izmir province.

Syrians and Afghans were among the migrants, who were attempting to illegally cross into Greece.

Turkey is the main route for refugees trying to cross into Europe, especially since the start of the civil war in Syria.