NBC News staff could see and hear mortars, grenades, machine-gun and rifle fire in Ras al-Ayn — although it remains unclear who was responsible.
The Kurdish-led Syrian Democratic Forces (SDF) — allies of the U.S. during the fight against the Islamic State militant group — claimed Friday that Turkish forces were not slowing down their assault.
"Despite the agreement to halt the fighting, air and artillery attacks continue to target the positions of fighters, civilian settlements and the hospital Serêkaniyê/Ras al-Ayn," Mustafa Bali, spokesman for the SDF, said in a tweet.
But at a press conference Friday, Turkish President Recep Tayyip Erdogan denied attacks were ongoing. "There is no question of clashes. This is all speculation, disinformation," he said.
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Turkish forces are remaining in the area, in accordance with Thursday's agreement, in order to ensure Kurdish forces withdraw, he added.
The Syrian Observatory for Human Rights, based in London, also claimed Turkish forces had renewed their bombardment of Ras al-Ayn early Friday, disrupting the brief "cautious calm" achieved immediately after the cease-fire was called.
NBC News has not independently verified what groups were behind the attacks.
However, cross-border artillery fire and airstrikes seen ahead of the agreement appeared to have halted Friday with no outgoing fire seen from the Turkish side of the border.
Turkey's invasion launched last week came just as President Donald Trump pulled U.S. troops from the area, a move that has been met with widespread criticism for being a seeming betrayal of Kurdish forces that are allied with the U.S. in the fight against ISIS.
On Friday, Erdogan said he informed Trump about the offensive in a phone call three days before the operation started.
Turkey has committed to a permanent cease-fire once the Kurds are cleared from the safe zone, but is under no obligation to withdraw its troops. Erdogan praised Pence and Trump in a tweet in response to Thursday's deal, saying their combined efforts would help "defeat terrorism."
"I am confident that this joint effort will promote peace and stability in our region," Erdogan said.
The Turkish leader also said he will hold further talks about the conflict in Syria with Russian President Vladimir Putin next week. "With these discussions, God willing, we will bring peace to the area," he said.
Kurdish forces were not party to the U.S.-brokered agreement with Turkey. It was not immediately clear whether they would comply, but Erdogan said Kurdish fighters were retreating.
However, a spokesman for the SDF told The Associated Press on Friday that its troops would not withdraw in accordance with the cease-fire because Ras al-Ayn remained under attack.
Mac William Bishop reported from Ceylanpinar, Turkey, and Linda Givetash from London.
Mac William Bishop
Mac William Bishop is a London-based multimedia producer covering international news.
Linda Givetash is a London-based producer for NBC News.