The battle for Ras al Ain raged as Turkey pursued a four-day-old, cross-border offensive against a Syrian Kurdish militia despite an outcry from the United States and European Union and warnings of possible sanctions unless Ankara desisted.
The rounds landed about 9pm within a few hundred yards of the base on Mistenur Hill, US officials said.
Despite the artillery fire, DeWalt said that all USA troops are accounted for with no injuries and have not withdrawn from Kobani.
Members of the Kurdish community in Montreal (Fondation Kurde Du Québec) and their allies say the attack could disrupt the stability of a fragile region and hinder progress against the Islamic State (Daesh).
"The explosion occurred within a few hundred meters of a location outside the Security Mechanism zone and in an area known by the Turks to have USA forces present", Navy Capt. Brook DeWalt said in a statement. "That's not something we ever would have done to a partner force".
SDF forces had then repelled the attackers and the road was reopened, it said. The service members vacated the outpost after the incident but returned on Saturday, according to a U.S. official and images circulating on social media.
"I lost too many friends over there not to be here", he said.
The Kurdish-led Syrian Democratic Forces (SDF) warn that the attacks have revived the jihadist group.
"This was not a mistake", said Brett McGurk, a former United States envoy in the region.
"This was not a mistake", he said.
Arab foreign ministers demanded on Saturday, following their meeting at the Arab League (AL) headquarters in Cairo, an "immediate and unconditional" withdrawal of the Turkish troops from northern Syria.
On Saturday, France said it would suspend all weapons exports to Turkey.
US President Donald Trump has faced a firestorm of criticism, even from his own domestic supporters, for abandoning a loyal ally and stands accused of giving Turkey a green light to launch the offensive after ordering American troops to pull back from the border.
"It's not an easy decision", she said.
The move immediately raised concerns that the United States was abandoning Syrian Kurds, who have been the closest USA partner in counter-terrorism operations against the Islamic State.
Turkey's defense ministry says the country's forces have captured a Syrian border city after clashes with Kurdish-led militias.
USA lawmakers introduced more legislation on Friday seeking stiff sanctions on Turkey over the offensive, underscoring unhappiness from both Democrats and President Trump's fellow Republicans in Congress over his Syria policy.
The Kurdish-led Syrian Democratic Forces (SDF) now hold thousands of suspected IS prisoners.
American military observers believe that Turkey may have been trying to send a message that it wanted the USA forces to leave the area while it continued its offensive against Kurdish positions near its border with Syria.
In response, Turkish Foreign Ministry spokesman Hami Aksoy said that "no one should doubt that we will respond in kind against each step to the full extent of reciprocity".
"The (Syrian rebel) national army took control of (Ras al Ain) town center this morning", a senior Turkish security official said.
Putin also said Russian forces in Syria were ready to leave the country as soon as new legitimate Syrian government tells Moscow it no longer needs its help.
SDF officials later said that none had successfully escaped.