A total of 504 foreign nationals have been taken into custody in Turkey either for being illegally in the country or attempting to travel illegally to European countries, security sources said.

A police operation in Istanbul's Zeytinburnu district on Tuesday led to the arrest of 143 foreigners including 139 Afghan nationals plus two Turkmen, one Uzbek and one Pakistani who entered the country illegally, a police source said Thursday.

The foreigners will be deported after being questioned by the police, according to the source who spoke anonymously due to restrictions over talking to the media.

Separately, 361 refugees and migrants including nationals of Nepal, Eritrea, Morocco, Somalia, Bangladesh, Afghanistan, Algeria, Tunisia and Syria were held in several districts of the northwestern province of Edirne on Thursday.

The foreign nationals were detained by border troops and gendarmes as they were attempting to illegally cross the borders with Greece and Bulgaria, a security source said.

The foreigners have been referred to the migration management authorities.

Turkey has been a main route for refugees trying to cross into Europe since especially the beginning of the civil war in Syria.