Ali Javanmardi from VOA's Persian Service contributed to this report from Irbil.

The World Food Program says more than 100,000 people have been displaced so far by the Turkish invasion of northern Syria.

The agency said the those displaced have come from the towns of Ras al-Ayn and Tal Abyad.

Kurdish-led Syrian Democratic Forces deny that Turkish forces have taken the border town of Ras al-Ayn as Turkey had claimed.

The Syrian Observatory for Human Rights says the civilian death toll resulting from Turkey's offensive has risen to 30.

Ankara launched the cross-border operation on Wednesday, saying it wants to clear a buffer zone in northern Syria of Syrian Kurdish forces, whom it sees as terrorist allies of Kurdish separatists in Turkey.

Turkey reported its first military fatality three days into its incursion into Syria. The defense ministry said three other soldiers were wounded, without giving any details. Civilian casualties also were reported in the Turkish-Syrian border region.

U.S. officials say an American military outpost in Kobane, in northeastern Syria has been evacuated after Turkish artillery shells landed nearby. The main U.S. base in Kobane was not affected, and the officials said they expect the evacuation of the outpost will be temporary.

NATO urged Turkey, an alliance member, to exercise restraint.

NATO Secretary General Jens Stoltenberg acknowledged Turkey's legitimate security concerns about the Syrian Kurdish fighters but warned that the offensive could "jeopardize" progress made against the Islamic State terror group that previously held territory in northern Syria.

Stoltenberg spoke at a news conference in Istanbul with Turkish Foreign Minister Mevlut Cavusoglu. Cavusoglu said Turkey expects solidarity from NATO against the threats it faces.

"I am very concerned by reports of civilian casualties on both sides of the border, and of large numbers of people moving inside Syria in the hope of avoiding the fighting," said Mark Lowcock, U.N. Under-Secretary-General for Humanitarian Affairs and Emergency Relief coordinator. He made the comments in a statement published Friday, the second day of a two-day visit to Ankara and the Turkish-Syrian border.

"I reiterate what the Secretary-General of the United Nations has said: that we urge all parties to exercise restraint, to act in line with their obligations under the U.N. charter and international humanitarian law, to respect the sovereignty and territorial integrity of Syria, and in particular to protect civilians and civilian infrastructure," Lowcock said.

Speaking to VOA Persian, SDF spokesman Mustafa Bali said people in northern Syria were "frustrated and disappointed" that President Donald Trump withdrew dozens of U.S. troops that had been stationed in northern Syria earlier this week, shortly before Turkey launched the offensive. The troops were part of a U.S. military deployment that has partnered with the SDF in the fight against IS.

"The United States didn't stop the Turks from doing this offensive," Bali said.

Trump has said he pulled out the U.S. troops because they had defeated IS and he did not want them to be caught up in an offensive that Ankara long had threatened to carry out against Syrian Kurdish forces. His administration has strongly criticized the Turkish offensive and denied green-lighting it.