The air strikes in Syria targeted the YPG, which Turkey considers to be the Syrian branch of the PKK, but is a key ally for Washington and a major component of the US -backed Syrian Democratic Forces (SDF), a Kurdish-Arab alliance fighting ISIS in Syria.
"We let the Turks know that the amount of time that was being provided for the strikes was inadequate for us to assure safety of our forces on the ground", said Dorrian.
The U.S. -backed Kurdish forces in northern Syria are threatening to pull out of the anti-ISIS coalition if the U.S. won't protect them from Turkish airstrikes on their positions.
Fighting broke out on Wednesday along the northeast Syria border between Turkish forces and Kurdish militiamen, a monitor said, a day after deadly Turkish air strikes on the area. Both Kurdish forces are close USA allies in the war against IS.
Dorrian said that the United States has sent military personnel to the affected site in Syria to assess the damage to SDF forces.
The US. later issued a statement expressing "serious concern" of Turkey's anti-terror operations in the region, implying the U.S.'s worries about the death of YPG terrorists, saying "The airstrikes led to the unfortunate loss of life of our partner forces in the fight against ISIS, including the Kurdish Peshmerga". "These are our partner forces".
Meanwhile, Turkish President Recep Tayyip Erdogan reportedly said that the attacks in Iraq and Syria will not stop until the elimination of the last "terrorist".
The Turkish foreign affairs ministry pushed back on these claims, stating that US and Russian forces were adequately informed "in line with the bilateral deconfliction arrangements regarding Syria and Iraq". The U.S. considers the YPG one of the most effective rebel groups fighting IS in Syria.
"Therefore, we demand and appeal to the worldwide community to intervene to put an end to this aggression and the ongoing violations on our territory", the SDF concluded. On April 26, strikes against outlawed Kurdistan Workers' Party (PKK) targets in Sinjar, northern Iraq, and Karaçok, Syria, killed 70 militants, but also killed up to six Peshmerga fighters from the KRG of northern Iraq. Syrian Democratic Forces continue to choke off Raqqa, the self-declared capital of the Islamic State caliphate.
"Well, to be clear, we provide weapons and equipment to the Syrian Arab Coalition, not the YPG", Dorrian said.
The coalition calls on all forces to remain focused on the fight to defeat ISIS, he said, which is the greatest threat to regional and worldwide peace and security.