"In a letter to Turkey's National Defense Minister Fikri Isik, the head of the Pentagon, James Mattis, announced his intention to provide Turkey with a list of arms supplied to the Kurdish YPG [People's Protection Units] formations," the ministry said.
It added that Mattis vowed "that the weapons will be returned after the victory over the Islamic State [Daesh] militants."
"Mattis said that US advisers are taking the necessary measures to prevent the export of weapons outside Syria," the Turkish ministry said.
On May 9, the Pentagon announced that President Donald Trump had approved a plan to arm Kurdish YPG in order to better fight against terrorism in Syria despite objections from Turkey.
Ankara considers the YPG to be affiliated with the Kurdistan Workers' Party (PKK), which is listed as a terror group in Turkey, the United States and the European Union.