ANKARA, Feb. 6 (Xinhua) -- Defying the U.S. warnings, Turkish President Recep Tayyip Erdogan on Tuesday vowed that Turkish troops would expand cross-border military operations from Syria's Afrin to Manbij.

"They (the U.S.) tell us don't come to Manbij, but we will come to Manbij to hand over the land to its original Arabic owners," Erdogan said in a speech to his ruling Justice and Development Party's parliamentary group in Ankara.

Erdogan blasted the U.S. for its military presence in Manbij with fighters from the People's Protection Units (YPG), the armed wing of the Democratic Union Party (PYD), which Ankara sees as a terror group affiliated with the banned Kurdistan Workers Party (PKK) which has been fighting for autonomy in Turkey's southeast.

Erdogan also criticized U.S. President Donald Trump and his predecessor Barack Obama for lying in pledging to pull the U.S. troops out of Manbij, which is 100 km east of Afrin.

"They said they will not stay in Manbij... Why don't you just go?" he asked.

Erdogan added that Turkey would launch an international initiative against the U.S. for arming the PYD and PKK.

Turkish troops launched "Operation Olive Branch" on Jan. 20 in a bid to remove the YPG militia from Syria's northwestern region of Afrin.

The U.S., which has cooperated with the YPG in fighting the terror group Islamic State in the past years, has urged Ankara to limit its military operations in Syria, while warning about the risk of a possible conflict with the U.S. troops based in Manbij if Turkish troops move on to capture the city.