ISTANBUL (AP) — Turkey's president has criticized NATO for not supporting his country's ongoing military operation against Syrian Kurdish fighters in Syria.

President Recep Tayyip Erdogan, speaking to reporters on Saturday, asked, "Hey NATO, where are you?" and accused the military alliance of double standards.

Erdogan said NATO member Turkey sent troops to conflict zones when requested, but did not receive support in return.

Turkey launched a solo military offensive against the Syrian Kurdish People's Protection Units or YPG on Jan. 20 to clear them from Afrin in northwestern Syria.

The country considers the YPG a terror organization, but its NATO ally, the United States, backs the fighters to combat the Islamic State group.

Erdogan urged NATO to come to Turkey's aid, saying its borders are "under threat right now."