Trump sent the letter to Erdoğan on Oct. 9 when Turkey launched an operation in northern Syria. The U.S. President also threatened to destroy the Turkish economy if Erdogan went ahead with the operation.
"You should sit down and respond to that letter in a way that protects the glory and honour of the nation. It will be within the diplomatic rules, but you are going to give him the answer he deserves. So you go to the United States to return the letter? That is nonsense. He definitely should not go," Republican People's Party (CHP) leader Kemal Kılıçdaroğlu said.
Erdoğan said on Friday that he would return the letter, which the ruling Justice and Development Party (AKP) officials said he threw the letter in the bin before launching the operation, to Trump during his visit to Washington on Nov. 13.
Following Turkey's operation, Trump imposed several sanctions on Turkey, however, he later lifted them after a ceasefire in northeast Syria was established.
"U.S. imposing sanctions on Turkey would benefit Erdoğan. Erdoğan would tie the ongoing economic crisis to the United States," Kılıçdaroğlu said.