Turkey had reacted angrily to suggestions that Trump's plan to withdraw troops was conditional on the safety of the US-backed Kurdish fighters, who are viewed as terrorists by the Turkish government. He, however, also urged the Kurds not to provoke Ankara.
Turkey says the YPG is tied to the Kurdistan Workers Party (PKK) which has been fighting a long guerrilla war for more Kurdish autonomy inside Turkey.
Secretary of State Mike Pompeo, who is on a whirlwind tour of the Middle East, took time to reassure Washington's Kurdish allies they would still be supported in the fight against Isis.
The US-led coalition on Saturday fired more than 20 missiles against jihadist positions, the observatory said.
Pompeo said he had spoken to his Turkish counterpart, Mevlut Cavusoglu, earlier on Saturday, adding that there are "many details still to be worked out", but that he was optimistic both sides could achieve "a good outcome there".
FILE - A US soldier sits atop his armored vehicle on a road near Manbij, Syria, April 4, 2018. "We will protect Kurds and other Syrians against all terrorist threats", Kalın added.
Turkey, however, remains firmly committed to removing what they call a Kurdish "terrorist" threat coming from the Euphrates River valley, and is actively preparing for a possible cross-border operation.
CoA emails Hardik Pandya, KL Rahul informing of suspensions
Even Pandya had earlier mentioned he had got carried away by the "nature of the show" while apologising for his comments on social media .
Trump said on Sunday the United States was starting the military pullout from Syria that he announced in December but that it would continue to hit Islamic State fighters there.
The president defended his decision to withdraw troops, saying any remaining IS fighters could be attacked from an unspecified "existing nearby base".
Trump also threatened to "devastate Turkey economically" if the country hit the Kurds living in Syria.
Maria Zakharova, a Russian Foreign Ministry spokeswoman, said it was important for Syrian Kurds and the Syrian government to start talking to each other in light of the USA withdrawal plans.
Mr Trump also said that Russia, Iran and Syria had been the biggest beneficiaries of USA action in Syria and it was time to bring American soldiers home. "Stop the ENDLESS WARS!" he continued.
Pompeo's remarks follow tensions between the U.S. and Turkey over the fate of Washington's allies in the fight against ISIS.
Trump's decision to call back USA troops in Syria, who were first deployed in 2015, was followed a day later by the resignation of Defense Secretary Jim Mattis, who wrote a letter to the president saying he had the right to have a secretary of defense "whose views are better aligned with yours".
Bali said ISIS fighters "realize that this battle is the battle to eliminate them".