QAMISHLI, Syria — Heckled by Kurds who feel betrayed, a long convoy of United States troops crossed into Iraq early Monday, accelerating a withdrawal of American forces from northern Syria that set the stage for the Turkish invasion of Kurdish-controlled land.

More than 100 American military vehicles left Syrian Kurdish territory in the early morning, according to a cameraman for the Reuters news agency who was at the border crossing.

Residents threw rocks and potatoes at the convoy as it drove through Qamishli, a major city in Kurdish-held territory. In video posted online by a local Kurdish news outlet, ANHA Hawar, men hurling potatoes at an armored vehicle shouted “No America” and “America liar,” in English.