The U.S. Secretary of State said in a statement that "The minister Pompeo expressed his support for the ongoing negotiations on north-east of Syria, warning at the same time of the potential devastating consequences of any unilateral Turkish military action in the region."
The two ministers met on the margin of NATO's celebration of the 70th anniversary of its establishment.
The U.S. Secretary of State also told his Turkish counterpart that he was "concerned that Turkey might have a missile defense system for the Russian S-400."
Pompeo also called for a "quick resolution of the issues related to the US citizens" and the Turkish employees working in the US diplomatic missions in Turkey, who are "unjustly detained" in the country.
The United States said on Monday it would stop shipping parts of Turkish F-35s and suspend joint manufacturing activities because Ankara bought the S-400 missile defense system from Russia.
The US-Turkish relations have been strained over issues, the most important of which are the Syrian affair and the purchase of Russian weapons.