On October 20, 1998, Turkey and Syria signed the Adana Agreement and established a joint agenda to fight the PKK and improve their political, economic, and security relations. Accordingly, the Syrian authorities expelled the head of the terrorist organization, Abdullah Öcalan, from Syria and declared that they stopped supporting the PKK. During the AKP era, the normalization of Turkish-Syrian relations gradually became more important. Turkey and Syria began to establish a relationship based on free economic activities and the free flow of people and goods. Political visits between Turkey and Syria were initiated by Erdoğan’s trips to Syria in 2004.