"Is it all simply because we are Kurds?".
In a hastily arranged press conference at the Pentagon, Joint Chiefs of Staff Chairman Gen. Mark Milley told reporters that he has personally ensured Turkey has "explicit grid coordinate detail" of the location of all 1,000 US troops stationed in Syria.
"They didn't help us with Normandy, as an example".
European diplomats in Brussels have responded cautiously to the idea of sanctions on Ankara though the invasion - which began Wednesday and was dubbed by Turkey "Operation Peace Spring" - has met with unanimous criticism.
In statements Thursday, Trump said that options for dealing with the situation included sending in "thousands" of American forces, a proposal he rejected; imposing severe economic sanctions on Turkey; or providing U.S. mediation between Turkey and the Kurds.
The U.S. has about 1,000 troops in Syria.
But he also added that U.S. troops would not get between the Turks and the Kurds in the fight.
Many have called the limited USA pullback a grave mistake.
He defended his abrupt decision to pull out of northern Syria, allowing Turkey to attack Kurdish towns, at a campaign rally in Minneapolis, Minnesota, on Thursday.
A contingent of U.S. Special Forces has been caught up in Turkish shelling against U.S. -backed Kurdish positions in northern Syria.
Esper told a Pentagon news conference that Washington is "greatly disappointed" by the Turkish incursion.
"We have seen people being displaced from locations along the border due to the conflict and are extremely anxious that the military intervention will threaten the safety and wellbeing of the Syrian people", the group said. They said the offensive threatens progress against the extremist Islamic State in Iraq and Syria (ISIS) by a global coalition, undermines stability of the region and exacerbates "civilian suffering".
The senior Pentagon official said that Turkish forces should be aware of US positions "down to the grid".
Eric Schwartz, president of Refugees International, an aid group, blasted Trump's policy shift and rounded on Turkish President Recep Tayyip Erdogan's "shockingly irresponsible" assault, which "will put lives at grave risk".
The statement said that Turkey was not targeting the USA troops and that precautions were taken to prevent damage to the US fortification. Esper announced Friday that he was sending dozens more fighter jets and additional air defenses to Saudi Arabia, beefing up efforts to defend against Iran. The administration threatened sanctions against Turkey earlier this year for its purchase of the Russian S-400 air defense system, but never followed through.
Five Islamic State fighters fled a jail there, and foreign women from the group being held in a camp torched tents and attacked guards with sticks and stones, the Kurds said.
"I hope we can mediate", Trump said when asked about the options by reporters. He lamented "the dramatic harm" done to the two nations' relationship. The operation targets the predominantly-Kurdish Syrian Democratic Forces (SDF) and Daesh*.
Milley, the chairman of the joint chiefs of staff, said the Turkish military operations across the border into Syria were still "relatively limited".
"Turkey's measure is an aggression against an independent country", Khatami said while addressing the Friday Prayers sermon in Tehran.
Kurdish forces have, until many took off for the front lines against Turkey, provided protection for U.S. installations.
The SDF have been the main allies of US forces on the ground in the battle against ISIL since 2014.
Ankara has long opposed USA support for the YPG in the fight against the Islamic State extremist group, arguing the militia is a "terrorist" offshoot of Kurdish insurgents inside Turkey.
President Donald Trump, whose order to pull back United States troops from the border this week effectively triggered the invasion, said Washington would now seek to broker a truce.
On Tuesday, he was praising Turkey for being a United States trading partner and assuring the Syrian Kurds (who were already by this time under Turkish assault) that the USA had not abandoned them.
The main goal of Turkey's "Operation Peace Spring", launched on October 9 in northern Syria, is to ensure the security of the border and to save the Syrian people from the oppression of terrorists, the Turkish Foreign Ministry said October 11.
The Pentagon had said before the operation began that the USA military would not support it, but it had not openly criticized the invasion.
On Friday, a small US military outpost near the Syrian border town of Kobani was hit by Turkish artillery fire, according to a USA official.