Washington, President Donald Trump is pushing back at criticism that his Syria withdrawal is damaging U.S. credibility, betraying Kurdish allies and opening the door for a possible resurgence of the Islamic State.

He touted a cease-fire agreement that seemed at risk as Turkey and Kurdish fighters differed over what it required and whether combat had halted.

“We’ve had tremendous success I think over the last couple of days,” Trump declared Friday. He added that “we’ve taken control of the oil in the Middle East” — a claim that seemed disconnected from any known development there.

He made the assertion twice Friday, but other U.S. officials were unable to explain what he meant.

Calling his Syria approach “a little bit unconventional,” the president contended that Turkish President Recep Tayyip Erdogan as well as the Syrian Kurdish fighters the Turks are battling agree that the U.S.-brokered cease-fire was the right step and were complying with it.

“There is good will on both sides & a really good chance for success,” he wrote on Twitter.

That optimism seemed at odds with Erdogan’s own words. He told reporters in Istanbul that Turkish forces would resume their offensive in four days unless Kurdish-led fighters withdraw “without exception” from a so-called safe zone 20 miles (30 kilometers) deep in Syria running the entire 260-mile (440-kilometer) length of the border with Turkey.

There was no sign of any pullout by the Kurdish-led forces, who accused Turkey of violating the cease-fire with continued fighting at a key border town.

They also said the accord covers a much smaller section of the border. And some fighters have vowed not to withdraw at all, dismissing the deal as a betrayal by the U.S., whose soldiers they have fought alongside against the IS.

Eric Edelman, a former U.S. ambassador to Turkey who served as the Pentagon’s top policy official during the George W. Bush administration, said he doubts Turkey and its Syrian proxies could control the entire border area from the Euphrates to Iraq without help from Russia or others.

“That’s a very big expanse of territory to hold, albeit a lot of it is uninhabited,” Edelman said. “That probably means they’ve cut already some deal with the Russians and the Iranians.” Even so, Trump insisted peace was at hand.

“There is a cease-fire or a pause or whatever you want to call it,” he said. “There was some sniper fire this morning,” as well as mortar fire, but that was quickly halted and the area had returned to a “full pause,” he said.

Trump also asserted that some European nations are now willing to take responsibility for detained IS fighters who are from their countries.

“Anyway, big progress being made!!!!” he exclaimed on Twitter.

Trump said nothing further about the European nations he now contends have agreed to take some of the IS fighters, a demand he has repeated often.

No European government announced an intent to take control of IS prisoners.

Speaking in Brussels after briefing NATO ambassadors on the Syria situation, Secretary of State Mike Pompeo said, “We’ve seen comments today from a number of countries who said they may well be prepared to take back these fighters.” He, too, identified no such countries.

At the Pentagon, Defense Secretary Mark Esper said U.S. troops are continuing their withdrawal from northern Syria. He also said no U.S. ground troops will participate in enforcing or monitoring the cease-fire.

“The force protection of our service members remains our top priority and, as always, U.S. forces will defend themselves from any threat as we complete our withdrawal from the area,” Esper told reporters.

One important unknown in the wake of Turkey’s military incursion, which began Oct. 9, is whether IS fighters who have been held by U.S.-allied Kurdish fighters known as the Syrian Democratic Forces will escape in large numbers.

Even before the Turkish offensive, some U.S. officials had noted signs that IS was seeking to regroup.

Officials have said a number of ISIS fighters, likely just over 100, have escaped custody since Turkey launched its invasion last week.

There are 11 prisons with IS detainees in the so-called safe zone between Tal Abyad and Ras al-Ayn.

Accounting for the broader border area that the Turks contend is the safe zone – that number grows to 16 prisons. It’s unclear exactly how many of those are currently under Turkish control – but as they push the Kurds out, the Turks are supposed to take control of the prisons.

Trump has been widely criticized for turning his back on the Kurds, who have taken heavy casualties as partners with the U.S. since 2016. Even some Republicans are taking aim.

“Withdrawing U.S. forces from Syria is a grave strategic mistake. It will leave the American people and homeland less safe, embolden our enemies, and weaken important alliances,” Sen. Majority Leader Mitch McConnell wrote Friday in a Washington Post opinion column.

Erdogan said Friday he and Trump share “love and respect,” but he also left little doubt that he was offended by an Oct. 9 letter from Trump telling him, “Don’t be a fool!” Erdogan told reporters Trump’s words were not compatible with “political and diplomatic courtesy” and would not be forgotten. He said he would “do what’s necessary” about the letter “when the time comes.” He did not elaborate.

While U.S. officials have insisted that Trump did not authorize Turkey’s invasion, the cease-fire codifies nearly all of Turkey’s stated goals in the conflict.