At least 420 undocumented migrants were held in northwestern Turkey, security sources said on Monday.
In the province of Kirklareli, gendarmes held the foreign nationals in Demirkoy, Kofcaz and Babaeski towns, said the sources on condition of anonymity due to restrictions on speaking to the media.
Undocumented migrants of Iraqi, Afghan, Pakistani and Syrian origins were trying to illegally cross into Europe, the sources added.
Separately, another 379 foreign nationals were held in Edirne, another northwestern province, while attempting an illegal border crossing to Europe via Turkey.
Among them were also Syrian, Iraqi, and Afghan nationals, apart from Palestinians, Libyans, Algerians, Iranians, and Bangladeshis.
They were later referred to the local migration authorities.
Meanwhile, two suspects were arrested for allegedly organizing the illegal border crossing.
Turkey has been the main route for refugees trying to cross into Europe, especially since 2011, the start of Syria's civil war.
Among the migrants held in 2017 in Turkey, the majority came from Pakistan -- around 15,000 -- followed by Afghans at around 12,000. Syrians totaled 10,000.
