U.S. says troops came under fire as Turkish forces push deeper into Syria

Turkish forces faced fierce resistance from U.S.-allied Syrian Kurdish fighters on the third day of Ankara's offensive in northern Syria, as casualties mounted, international criticism of the campaign intensified and estimates put the number of those who fled the violence at 100,000.In a complicating twist, Washington said its troops also came under fire from NATO ally Turkey.

No U.S. troops were hurt in Friday's explosion at the small U.S. outpost, according to a Pentagon spokesperson, and the artillery strike marked the first time a coalition base was in the line of fire since Turkey's offensive began.

U.S. officials said the Americans have vacated the post on a hill outside the town of Kobane and added that a large base in the town was not affected by the shelling. The officials spoke anonymously because they were discussing an ongoing military operation.

Turkey said the U.S. was not targeted and its forces were returning fire after being targeted by Kurdish fighters about half a mile from the U.S. outpost. The Turkish Defence Ministry said it ended the strike after communicating with the U.S.

Navy Capt. Brook DeWalt, a Pentagon spokesperson, says the artillery explosion came within a few hundred meters of the area where U.S. troops were.

The artillery strike so close to American forces showed the unpredictable nature of the conflict days after U.S. President Donald Trump said he was getting U.S. troops out of harm's way.

Earlier,Turkey said it captured more Kurdish-held villages in the border region, while a hospital in a Syrian town was abandoned and a camp of 4,000 displaced residents about 12 kilometresfrom the frontier was evacuated after artillery shells landed nearby.

Reflecting international fears that Turkey's offensive could revive the Islamic State in Iraq and Syria (ISIS), two car bombs exploded outside a restaurant in the Kurdish-controlled urban centreof Qamishli, killing three people, and the extremists claimed responsibility. The city also was heavily shelled by Turkish forces.

Kurdish fighters waged intense battles against advancing Turkish troops that sought to take control of two major towns along the Turkish-Syrian border, a war monitor said.

The UNestimated the number of displaced at 100,000 since Wednesday, saying that markets, schools and clinics also were closed. Aid agencies have warned of a humanitarian crisis, with nearly a half-million people at risk in northeastern Syria.

On Sunday,Trump cleared the way for Turkey's air and ground assault after he pulled U.S.troops from their positions near the border, drawing swift bipartisan criticism that he was endangering regional stability and abandoning Syrian Kurdish forces that brought down ISIS inSyria.

Trump had said at the time that the estimated 1,000 U.S. troops were not in harm's way from the Turkish offensive. Rami Abdurrahman, head of the war monitor Syrian Observatory for Human Rights, said the U.S. base was on a hill near the Kurdish-held town of Kobani, which had come under heavy Turkish fire.

U.S. Defence Secretary Mark Esper said Washington is not abandoning its Syrian Kurdish allies and pushed back hard for NATO-ally Turkey not to launch the operation. He said U.S. troops are still working with Kurdish fighters.

Despite the criticism, Turkish President Recep Tayyip Erdogan said his country "will not take a step back" from its offensive.

"We will never stop this step. We will not stop no matter what anyone says," he said in a speech Friday.

Plumes of black smoke billowed Friday from Tel Abyad as Turkey continued bombarding the area in an offensive that was progressing "successfully as planned," the Turkish Defence Ministry said.

Turkey claims to have killed hundreds

Turkey considers the Syrian Kurdish fighters to be terrorists linked to a Kurdish insurgency inside Turkey and says the offensive is a counterterrorism operation necessary for its own national security.

The Turkish Defence Ministry said four of its soldiers have been killed since Wednesday, with three wounded. Defence Minister Hulusi Akar said 342 "terrorists" Ankara's term for Syrian Kurdish militiamen have been killed so far. The figure could not be independently verified.

The Kurdish-led force said 22 of its fighters were killed since Wednesday.

The Kurdish militia has fired dozens of mortars into border towns inside Turkey in the past two days, including Akcakale, according to officials in two provinces on the Turkish side. They said at least nine civilians were killed, including a nine-month-old boy and three girls under 15.

'Damn the PKK!'

Mourners in Akcakale carried the coffin of the slain boy, Mohammed Omar Saar, as many shouted, "Damn the PKK!" referring to the Kurdish insurgent group in Turkey linked to Syrian Kurdish fighters. The PKK is considered a terrorist group by Turkey, the United States and other countries.

One attackhit the town of Suruc, and a child in the town of Ceylanpinar died of his wounds Thursday night, the Anadolu Agency reported.

On the Syrian side, seven civilians have been killed since Wednesday, activists said.

Russian President Vladimir Putin said he doubtedthe Turkish army has enough resources to take control of prison camps in the region housing ISISdetainees, and he fears the captured fighters "could just run away," leading to a revival of the militant group.

"We have to be aware of this and mobilize the resources of our intelligence to undercut this emerging tangible threat," Putin said during a visit to Turkmenistan.

The Syrian Kurdish forces had been holding more than 10,000 ISIS members, but they said they are being forced to abandon some of those positions to fight the Turkish invasion.

Separately, NATO Secretary General Jens Stoltenberg urged Ankara to exercise restraint, although he acknowledged what he said was Turkey's legitimate security concerns about the Syrian Kurdish fighters.

Turkey expects solidarity

In a news conference with Turkish Foreign Minister Mevlut Cavusoglu, Stoltenberg also expressed concernthat the Turkish offensive could "jeopardize" gains made against ISIS. Cavusoglu said Turkey expected solidarity from its allies.

"It is not enough to say you understand Turkey's legitimate concerns;we want to see this solidarity in a clear way," he said.

The White House also put Turkey on notice it could face new "powerful sanctions" and that the U.S. will "shut down the Turkish economy" if Ankara goes too far, with U.S. Treasury Secretary Steven Mnuchin saying Washington hopes it will not have to use its new, expanded sanctions authority that Trump has authorized.

The Turkish operation aims to create a corridor of control along Turkey's border that clears out the Syrian Kurdish fighters. Such a "safe zone" would end the Kurds' autonomy in the area and put much of their population under Turkish control. Ankara wants to settle twomillion Syrian refugees, mainly Arabs, in the zone.

Doctors Without Borders said the fighting forced it to shut down a hospital it supports in the border town of Tel Abyad serving more than 200,000 people because most of the residents had to leave, including the medical staff and their relatives.

The group said aid groups had to suspend or limit operations in the al-Hol camp, home to more than 70,000 women and children located 50 kilometresfrom the Turkish border, as well as the Ain Eissa camp.