Turkish President Recep Tayyip Erdogan put US President Donald Trump's letter "in the bin", Report informs citing the BBC.
In the letter dated 9 October, and sent after US troops were pulled out of Syria, Mr Trump told Mr Erdogan: "Don't be a tough guy. Don't be a fool!"
Turkish presidential sources told BBC Turkish that the letter was "thoroughly rejected" by Mr Erdogan.
On the day the letter was received, Turkey launched a cross-border offensive against Kurdish-led forces.
"Let's work out a good deal! You don't want to be responsible for slaughtering thousands of people, and I don't want to be responsible for destroying the Turkish economy - and I will," Mr Trump said in the letter.
'Don't be a tough guy. Don't be a fool!': Trump writes at conclusion.