As a Turkey-backed offensive neared Manbij, Syria, the head of U.S. Central Command said withdrawal was “not something we are looking into.”
“It is a strange incident,” Turkish media analyst Nate Schenkkan told Newsweek.
The White House said Trump had told his Turkish counterpart in a phone call to “limit its military actions.”
Neither Russian, Syrian nor U.S. forces have moved in to stop the Turkish invasion aimed at ousting Pentagon-backed Kurds from the enclave of Afrin.
China, Egypt, India, Iraq, Saudi Arabia, Sudan, Syria and Turkey were among those looking to get their hands on the S-400 missile defense system.
ISIS could be helped by a string of Turkish military strikes against Kurdish groups in northern Syria, U.S. Secretary of Defense James Mattis warned Tuesday.
After ISIS was mostly defeated in the east, the Syrian military set its sights on rebel-held Idlib, while Turkey targeted U.S.-backed Kurds in Afrin, Aleppo.
The government is advertising Aleppo and other Syrian cities at an event in Madrid.
Turkey and Syrian rebels have launched a joint operation against Syrian Kurdish forces, putting the U.S. and Russia in a difficult position.
China's long-term global economic and security goals fit in line with a victory for Syrian President Bashar al-Assad.
Why the Kremlin is using mercenaries to fight its foreign wars.
The State Department has classified these 11 nations as "Do not travel."
Turkey and Russia have also condemned the plans for the 30,000-strong unit.
Turkey's Deputy Prime Minister called the U.S.-led coalition's decision to set up a border security force a "provocative" move.
The U.S.'s highest-ranking enlisted soldier said the coalition would beat ISIS fighters to death with shovels if they didn't give up.
A year after winning Aleppo, the Syrian military and its Russian ally launched a devastating offensive against the last rebel province of Idlib.
Russia used electronic and conventional warfare to take down a baker's dozen drones.
Leading NATO and Russian commanders will have their first meeting since 2013, when Obama banned talks, blaming Putin for the crisis in Ukraine.
"In the skies over Syria, it's really just been a treasure trove for them to see how we operate," Lieutenant General VeraLinn "Dash" Jamieson said.
Syria and Israel technically remain at war after years of animosity between the neighboring states, which both claim the Golan Heights.
"On seeing our Western coalition partners in the air, we always tailed them, as pilots say, which means a victory in real combat," a top Russian general said.