(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.
'Security threat' forces closing of US Embassy in Turkey
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.
There have been tensions between the United States and Turkey lately over the Trump administration's decision to provide weapons and equipment to Kurdish elements of the opposition Syrian Democratic Forces.
Ankara, which criticized the move, sees such Kurdish groups as linked to the Kurdistan Workers' Party, or PKK -- a separatist group that has waged a decade's long insurgency against the Turkish government.
Turkey launched an operation targeting Kurdish groups in Afrin in January, shortly after the US coalition announced plans to work with SDF elements to help stabilize areas of Syria that had been captured from ISIS.
Another source of tension between the United States and Turkey involves a Muslim cleric named Fethullah Gulen, who has been living in exile in the United States. Turkish President Recep Tayyip Erdogan believes Gulen orchestrated the failed 2016 coup attempt and has urged the United States to extradite him. But the United States has refused to do so.
The embassy advised Americans to steer clear of the embassy, stay away from large crowds, let friends and family members know about safety status and monitor the local media outlets.
"Heighten your personal security posture and awareness if you choose to visit popular tourist sites, shopping malls, shopping districts, and sports and entertainment venues," the security alert said.
During the closing, the embassy said it will provide "only emergency services."
"Routine services, such as passport renewals including lost or stolen passports, reports of birth abroad, and notarial services, are not considered emergencies," the alert said. "Requests for these services will be processed through our online appointment system once the Embassy reopens. Visa interviews and other routine services are canceled; applicants will be informed directly of steps to take."