According to the Anadolu news agency, a counterterror operation was held in the city of Samsun.
The US Embassy in Turkey will remain closed on Tuesday due to a security threat, the diplomatic mission said in a statement in the wake of the news.
Two of the suspects were arrested on a bus on a highway between the Samsun and Ankara. Two others were detained in Samsun.
LATEST — 4 suspected Daesh terrorists planning to attack the US Embassy in Ankara have been detained by Turkish authorities in northern Samsun provincehttps://t.co/W0OFmtUPOm— DAILY SABAH (@DailySabah) 5 марта 2018 г.
Police are in search of other suspects, the source added.
Earlier, in another operation, four Iraqi nationals were arrested for their alleged links to the Daesh terrorist group.
Daesh terrorists have committed a number of major terrorist attacks in Europe and around the world, attacking such countries as the United States, Great Britain, France and Germany.
*Daesh (also known as ISIS/ISIL/IS) is a terrorist group banned in Russia