Turkey launched airstrikes, fired artillery and began a ground offensive against Kurdish fighters in northern Syria on Wednesday after U.S. troops pulled back from the area, paving the way for an assault on forces that have long been allied with the United States.

Turkish President Recep Tayyip Erdogan announced the start of the campaign, which followed an abrupt decision Sunday by U.S. President Donald Trump that American troops would step aside to allow for the operation.

Trump’s move drew bipartisan opposition at home and represented a shift in U.S. policy that essentially abandoned the Syrian Kurdish fighters who have been America’s only allies in Syria fighting the Islamic State group. After Erdogan announced the offensive, Trump called the operation “a bad idea.”

There were signs of panic in the streets of residential areas close to the borders as civilians fled on foot, in cars and with rickshaws piled with mattresses and a few belongings. They included people who’d fled from the Islamic State group only few years ago.

At least seven civilians and one member of the Kurdish-led force known as the Syrian Democratic Forces were killed in the Turkish bombardment, Kurdish activists and a Syria war monitor said.

Near the town of Qamishli, plumes of smoke rose from an area close to the border after activists reported an explosion nearby. By nighttime, there were fires in one of the town’s neighborhoods, apparently ignited by the shelling.

Turkey’s Defense Ministry said Turkish ground forces, joined by allied Syrian opposition forces, had moved across the border into Syria. Shortly after, SDF spokesman Mustafa Bali said its fighters had repelled the Turkish ground attack in Tal Abyad.

Earlier, a U.S. defense official and a Kurdish official in Syria said the SDF has suspended operations against IS militants because of the Turkish operation. The officials who confirmed the suspension spoke on condition of anonymity because they were not authorized to provide details on the situation.

Turkey’s campaign — in which a NATO member is raining down bombs on an area where hundreds of U.S. troops are stationed — drew immediate criticism and calls for restraint from Europe. In his statement, Trump emphasized that there are no American soldiers in the area under attack.

“Our mission is to prevent the creation of a terror corridor across our southern border, and to bring peace to the area,” Erdogan said in a tweet announcing what he called “Operation Peace Spring.”

He said that Turkish forces, with Ankara-backed Syrian fighters known as the Syrian National Army, had begun to eradicate what he called “the threat of terror” against Turkey.

Minutes before Erdogan’s announcement, Turkish jets began pounding suspected positions of Syrian Kurdish forces in the town of Ras al Ayn, according to Turkish media and Syrian activists. The sound of explosions could be heard in Turkey.

It was difficult to know what was hit in the first hours of the operation.

Mustafa Bali, a spokesman for the U.S.-backed Syrian Democratic Forces, said Turkish warplanes were targeting “civilian areas” in northern Syria, causing “a huge panic” in the region.

The Britain-based Syrian Observatory for Human Rights said those killed in the Turkish bombardments included two Christian Assyrians in Qamishli, a married couple and their child, a man in a village outside of the town of Tal Abyad, and a child in a village west of Qamishli.

Before Turkey’s attack, Syrian Kurdish forces that are allied with the United States warned of a “humanitarian catastrophe.”

The Turkish operation meant to create a “safe zone” carries potential gains and risk for Turkey by getting even more deeply involved in the Syria war. It also would ignite new fighting in Syria’s 8-year-old war, potentially displacing hundreds of thousands.

A resident of Tal Abyad said one of the bombs hit an SDF office, and he fled with his wife and mother by car to Raqqa, nearly 100 kilometers (60 miles) to the south, to flee the bombing. The resident, who gave his name as Maher, said the road to Raqqa was packed with vehicles and families, some fleeing on foot “to get away from the bombing.”

“People fled and left everything behind,” he said in a text message after he reached safety.

Turkey has long threatened to attack the Kurdish fighters that Ankara considers terrorists allied with a Kurdish insurgency in Turkey. Expectations of an invasion increased after Trump’s announcement Sunday, although he also threatened to “totally destroy and obliterate” Turkey’s economy if the Turkish push went too far.

U.S. critics said he was sacrificing an ally, the Syrian Kurdish forces, and undermining Washington’s credibility. Republican Sen. Lindsey Graham, a Trump ally, told “Fox & Friends” that if Trump “follows through with this, it would be the biggest mistake of his presidency.”

Trump later said the U.S. “does not endorse this attack and has made it clear to Turkey that this operation is a bad idea.”

Trump said he made clear from the start of his political career that “I did not want to fight these endless, senseless wars — especially those that don’t benefit the United States. Turkey has committed to protecting civilians, protecting religious minorities, including Christians, and ensuring no humanitarian crisis takes place — and we will hold them to this commitment.”

NATO Secretary-General Jens Stoltenberg, while noting that Turkey “has legitimate security concerns” after suffering “horrendous terrorist attacks” and hosting thousands of refugees, said the country should not “further destabilize the region” with its military action in Syria.

German Foreign Minister Heiko Maas condemned the offensive, saying it will “further destabilize the region and strengthen IS.” The operation also was criticized by European Commission President Jean-Claude Juncker.

The EU is paying Turkey 6 billion euros ($6.6 billion) to help the country cope with almost 4 million Syrian refugees on its territory in exchange for stopping migrants leaving for Europe.

Fahrettin Altun, the Turkish presidency’s communications director, urged the international community to rally behind Ankara, which he said would take over the fight against the Islamic State group.

Turkey aimed to “neutralize” Syrian Kurdish militants in northeastern Syria and to “liberate the local population from the yoke of the armed thugs,” Altun wrote in a Washington Post column published Wednesday.

Erdogan discussed the incursion by phone with Russian President Vladimir Putin. Erdogan’s office said he told Putin the military action “will contribute to the peace and stability” and allow for a political process in Syria.

In its call for a general mobilization, the local civilian Kurdish authority known as the Autonomous Administration of North and East Syria asked the global community to live up to its responsibilities as “a humanitarian catastrophe might befall our people.”

The Kurds also said they want the U.S.-led coalition to set up a no-fly zone in northeastern Syria to protect the civilian population from Turkish airstrikes.

The U.S.-backed Syrian Kurdish group urged Moscow to broker talks with the Syrian government in Damascus in light of the Turkish operation. The Syrian Kurdish-led administration said it is responding positively to calls from Moscow encouraging the Kurds and the Syrian government to settle their difference through talks.

Syria’s Foreign Ministry condemned Turkey’s plans, calling it a “blatant violation” of international law and vowing to repel an incursion.

Russian Foreign Minister Sergey Lavrov accused Washington of playing “very dangerous games” with the Syrian Kurds, saying the U.S. first propped up the Syrian Kurdish “quasi state” in Syria and now is withdrawing support.

“Such reckless attitude to this highly sensitive subject can set fire to the entire region, and we have to avoid it at any cost,” he said in Kazakhstan.

Earlier Wednesday, three IS militants targeted the Kurdish-led Syrian Democratic Forces in Raqqa, once the de facto IS capital at the height of the militants’ power. An activist collective in Raqqa reported an exchange of fire and an explosion; the Observatory said two IS fighters engaged in a shootout before blowing themselves up.

IS claimed responsibility, saying one of its members killed or wounded 13 SDF members.

The SDF, which holds thousands of IS fighters in detention facilities in northeastern Syria, has warned that a Turkish incursion might lead to the resurgence of the extremists. The U.S.-allied Kurdish-led force captured the last IS area controlled by the militants in eastern Syria in March.

(AP)