ANKARA, Turkey (AP) — A Turkish prosecutor's office says police have detained 12 suspected Islamic State militants in the capital of Ankara and are searching for eight others.

A statement from the Ankara chief prosecutor's office says the suspects were nabbed in a police operation on Monday. It says all the suspects are foreigners, without providing detail on their nationalities.

According to the statement, they are suspected of trying to recruit members for the extremist group and were allegedly in contact with people in "conflict zones."

The detentions came as the U.S. Embassy in Ankara was closed on Monday due to an unspecified security threat.

A statement posted on the embassy's web page urged U.S. citizens to avoid the embassy in Ankara as well as large crowds and to "keep a low profile."