Erdogan made the announcement while speaking to reporters at the Ankara Esenboga Airport before leaving for an official visit to Pakistan.
Okem was the chief adviser on foreign policy to the prime minister prior to his latest appointment.
On Tuesday, Israel appointed its first ambassador to Turkey in six years. Eitan Na’eh, deputy ambassador to the U.K. since 2013, will be the new envoy to Ankara, the Israeli Foreign Ministry had announced. Na’eh previously worked in the Ankara embassy in 1993 and also served as Israel’s ambassador to Azerbaijan.