Turkey has extended the deadlines to file Income and Corporate Provisional Tax Return for 2020 1st Provisional Tax Period (January-February-March) and to pay the accrued taxes, from 18 May 2020 to 28 May 2020.
Please see this link for the full text of the Tax Procedural Law Circular numbered 130 and dated 12 May 2020 of the Turkish Revenue Administration (Only available in Turkish).