U.S. President Donald Trump imposed sanctions on Turkey on Oct. 14 and demanded its NATO ally to halt a military offensive in northeast Syria that is rapidly reshaping the battlefield of the world’s deadliest ongoing war.

Trump, who gave what critics say was a de facto green light for Turkey’s operation by ordering U.S. forces to pull out from the conflict area, requested the ceasefire in a call with President Recep Tayyip Erdoğan.

“The United States of America simply is not going to tolerate Turkey’s invasion in Syria any further. We are calling on Turkey to stand down, end the violence and come to the negotiating table,” Vice President Mike Pence told reporters in front of the White House, adding that the U.S. didn’t give Ankara the “green light” for it to “invade Syria.”

With lawmakers in the U.S. Congress moving to impose sanctions of their own, Trump issued an executive order authorizing sanctions against current and former officials of the Turkish government for contributing to Turkey’s military operation in northern Syria.

In a statement, Trump stated he had increased tariffs on the imports of Turkish steel back to 50 percent, six months after they were reduced, and would immediately end negotiations on what he described as a 2$100 billion’ trade deal with Turkey.

“Unfortunately, Turkey does not appear to be mitigating the humanitarian effects of its invasion,” Trump said, while vowing to swiftly destroy the Turkish economy if it carried on with “this dangerous and destructive path.”

Trump said his executive order would enable the U.S. to impose sanctions on those current or former Turkish officials who may be involved in human rights abuses. He said it will authorize sanctions such as the freezing of property assets and barring entry into the U.S.

Treasury Secretary Steven Mnuchin said the U.S. had imposed sanctions on Turkey’s ministers of defense, interior and energy, as well as their departments.

Upon harsh criticism from Republicans and Democrats alike for abandoning the Kurdish allies, Trump said Turkey’s action is precipitating a humanitarian crisis and “setting conditions for possible war crimes”. Still, he made clear he had no plans to reverse his decision to withdraw.

“As I have said, I am withdrawing the remaining United States service members from northeast Syria,” said Trump.

The move was quickly criticized as too little, too late by the top Democrat in Congress.

“His announcement of a package of sanctions against Turkey falls very short of reversing that humanitarian disaster,” said U.S. House of Representatives Speaker Nancy Pelosi.

Republican U.S. Senator Lindsey Graham, who has been critical of Trump’s decision to pull U.S. troops, said on Oct. 14 he strongly supported Trump’s decision to impose sanctions on Turkey.

“The President’s team has a plan and I intend to support them as strongly as possible, and to give them reasonable time and space to achieve our mutual goals,” Graham said in a statement.

A statement from Senate Democratic leader Chuck Schumer and Democratic senators Robert Menendez and Jack Reed said the only person who is able to “immediately stop this tragedy unfolding is the president himself.”

“The first step when Congress returns to session this week is for Republicans to join with us in passing a resolution making clear that both parties are demanding the president’s decision be reversed,” they said.

Germany criticizes Trump

A day later, German Vice Chancellor Olaf Scholz criticized Trump for not having coordinated his decision to impose sanctions against Turkey, adding that the EU is discussing its options and should act together.

“It’s crucial that we coordinate our actions internationally, that’s the most important thing in this situation. This also applies to the European Union,” Scholz told Reuters in an interview.

A day after Trump’s announcement regarding sanctions, Turkish Foreign Minister Mevlüt Çavuşoğlu talked to his U.S. counterpart Mike Pompeo on the phone.

The content of the phone call was not announced.

As part of its Operation Peace Spring, carried out with Syrian rebels, Turkey aims to clear its Syrian border from the People’s Protection Units (YPG), the main element of Washington’s Kurdish-led ally, the Syrian Democratic Forces (SDF), which has been a key U.S. ally in dismantling the jihadist “caliphate” set up by ISIS militants in Syria.

Ankara regards the YPG as a terrorist group due to its links with the Kurdistan Workers’ Party (PKK), with which the country has been battling for over 30 years and which is designated as a terrorist organization by Turkey, the U.S. and the EU.

Russia-backed Syrian forces on Oct. 14 rapidly took advantage of the abrupt U.S. retreat in Syria to move inside territory held by the previously U.S.-backed Kurdish forces south of the Turkish border. Washington had announced plans for a full withdrawal from northern Syria less than 24 hours earlier.

Washington’s former Kurdish allies maintained they welcomed the government troops as an emergency step to help fend off the Turkish assault, launched on Oct. 9 after what the Kurds called a U.S. betrayal.

Republican Senate Majority Leader Mitch McConnell, better known for his backing of Trump, joined his critics to express concern over the Syria pullout, saying it would “invite the resurgence” of ISIS.

“Such a withdrawal would also create a broader power vacuum in Syria that will be exploited by Iran and Russia, a catastrophic outcome for the United States’ strategic interests,” he said in a statement.

The Trump administration denied that the pull-out of its troop was what triggered the Turkish offensive.

“I can tell you with complete confidence that nothing that we did one way or the other was going to deter the Turks from what they wanted to do,” a senior Trump administration official said.

Thousands of militants from the SDF have died since 2014 battling ISIS in partnership with the U.S., a strategy the Trump administration had perpetuated after inheriting it from his predecessor, Barack Obama.

Trump says he aims to withdraw the U.S. from “endless” wars in the Middle East.

“Anyone who wants to assist Syria in protecting the Kurds is good with me, whether it is Russia, China, or Napoleon Bonaparte,” Trump wrote on Twitter earlier on Oct. 14.

“I hope they all do great, we are 7,000 miles away!” he added.

Erdoğan dismisses ‘threats’

In a speech during a visit to Azerbaijan, Erdoğan said: “We are determined to continue the operation until the end, without paying attention to threats.”

“Our battle will continue until ultimate victory is achieved,” he added.

The Turkish Defense Ministry on Oct. 15 said 595 militants had been “neutralized” since the operation began, while Erdoğan said that a 1,000 kilometer square area was “saved from the invasion of terrorists.”

Ankara uses the word “neutralize” to describe the killing, wounding or capture of militants.

The U.S. exit leaves Turkey and Russia, as well as Iran – Assad’s main Middle East ally – as Syria’s undisputed foreign power brokers. Ankara and Moscow both predicted they would avoid conflict in Syria, even as the front line between them will now spread across the breadth of the country.

“There are many rumors at the moment. However, especially through the embassy and with the positive approach of Russia in Kobani, it appears there won’t be any issues,” Erdoğan said when asked about the prospect of confrontation with Russia.

Kobani, on the Turkish border, is one of the first Kurdish-held cities where reports emerged of a possible Syrian government deployment.

Trump also spoke to the commander of the SDF, General Mazloum Kobani Abdi. Mazloum expressed concerns about the Syrian city of Kobani and asked Trump to raise that issue directly with Erdoğan, Pence said.

Trump raised the issue with Erdoğan, who expressed a firm commitment not to attack Kobani, said Pence.

Kremlin spokesman Dmitry Peskov dismissed the suggestion that Russia could clash with Turkish forces. “We wouldn’t even like to think of that scenario,” he said.

The fighting has raised concerns that the Kurds would be unable to keep thousands of ISIS jihadists in jail and tens of thousands of their family members in camps.

The region’s Kurdish-led administration claimed 785 ISIS-affiliated foreigners escaped a camp at Ain Issa over the weekend. The British-based war monitor Syrian Observatory for Human Rights, citing sources in the camp, said the number who escaped was smaller, around 100.

Erdoğan and Turkish Defense Minister Hulusi Akar, however, denied the aforementioned reports.

Pentagon chief to urge NATO allies

U.S. Defense Secretary Mark Esper said he would call on NATO allies to “take collective and individual” actions against Turkey when he meets defense chiefs in Brussels next week.

In a statement, the Pentagon chief said that it will press NATO allies to take “diplomatic and economic measures,” adding that Turkey’s military action “was unnecessary and impulsive” and could result in the resurgence of ISIS.

Republican and Democratic leaders of the U.S. Congress have announced plans to impose their own sanctions. But Turkey’s trade with the United States is a fraction of its trade with Europe.

China, meanwhile, urged Turkey on Oct. 15 to stop its military offensive in Syria and “get back on the the right track.”

Chinese Foreign Ministry spokesman Geng Shuang made the comments at a daily briefing in Beijing.

Britain is to halt new arms export licences to Turkey as a result of its concern over Ankara’s military operation, the country’s foreign minister Dominic Raab said on Oct. 15.

“The UK government takes its arm export control responsibilities very seriously and in this case, of course, we will keep our defense exports to Turkey under very careful and continual review,” Raab told parliament.

“No further export licences to Turkey for items that might be used in military operations in Syria will be granted while we conduct that review.”

Italy, the top arms exporter to Turkey last year, also joined a ban on selling weapons and ammunition to Ankara after a weekend decision by France and Germany to suspend sales, and Spain signaled it was ready to do so.

Erdoğan, Macron to hold phone call

British Prime Minister Boris Johnson and French President Emmanuel expressed deep concern at Turkey’s offensive and agreed to stay in close contact in a call on Oct. 15, Johnson’s spokesman said.

Earlier, Erdoğan had explained to Macron the aims of Turkey’s operation in northeastern Syria in a phone call, the Turkish presidency said.

Erdoğan said the operation would contribute to regional and global peace and stability, the presidency said.

EU countries have threatened to impose sanctions on Turkey over the assault. But at a meeting on Oct. 14 they agreed not to impose an embargo. Member countries would instead consider their own restrictions on sales of weapons, a measure likely to be brushed off as trivial, as arms account for just 45 million euros out of a Turkey-EU trade worth more than 150 billions euros.

Yet in a potentially more damaging blow, German car-maker Volkswagen said it was postponing a final decision on whether to build a 1 billion euro ($1.1 billion) plant in Turkey, citing concern over “current developments” after international condemnation of the incursion.

Turkey’s Foreign Ministry said it rejected and condemned decisions taken by the EU following Ankara’s Syria offensive and drilling activities in the eastern Mediterranean.

Ankara will seriously examine its cooperation with the EU on certain areas due to its “unlawful and biased” attitude, the foreign ministry said.

Stoltenberg ‘concerned’ about offensive

NATO, meanwhile, is concerned over the consequences of Turkey’s military operation on the fight against ISIS, Secretary General Jens Stoltenberg said on Oct. 15.

“I’m concerned about the consequences for the gains we have made in fighting our common enemy Daesh,” he told reporters, using an Arabic acronym for the jihadist group.

Mercy Corps said it is suspending operations and evacuating foreign staff from northeast Syria, where fighting has uprooted more than 130,000 people in recent days.

The international aid agency, which had been delivering aid to northeast Syria since 2014, said it had been providing civilians with fresh water and other basic needs since Turkey launched its offensive.

“We just cannot effectively operate with the heavy shelling, roads closing, and the various and constantly changing armed actors in the areas where we are working,” Made Ferguson, Mercy Corps’ Deputy Country Director for Syria said in the statement.