(CNN) The US Embassy in Turkey told American citizens it is closed to the public Monday because of a "security threat," and advised them to "keep a low profile," the embassy said in a security alert.

The embassy, located in the Kavaklidere district of Ankara, said it "will announce the reopening once it resumes services." The alert was issued Sunday.

The nature of the threat was not disclosed. Turks have been the victims of terror over recent years, and the government suspects ISIS, Kurdish militants and far-left groups.

The DHKP-C, or Revolutionary People's Liberation Party-Front, a far-left group, claimed responsibility for a 2013 suicide bombing at the US Embassy in Ankara.

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