The Turkish Foreign Ministry announced the freeze on Wednesday, stating that it came into effect after a series of meetings between the Foreign Ministry, the Finance Ministry's Financial Crimes Investigation Board (MASAK) and the Banking Regulation and Supervision Agency (BDDK).
Along with the $500 million in the Syrian president's personal accounts, banks also plan to freeze an estimated $150 million which Syrian state banks are currently holding in their Turkish counterparts.
Turkish authorities first announced their willingness to consider a bank freeze in early October, and cited the regime's continued refusal to halt anti-protester violence as reason for this week's decision.
The measure comes as part of a decision by the Arab League and Turkey in late November to enact comprehensive sanctions against businesses close to the regime. It was the first time the Arab League had agreed to impose sanctions on one of its own members. Foreign Minister Ahmet Davutoğlu said of the sanctions in early December that they signaled the "end of the road" for any further negotiations between Ankara and Damascus.