Syrian dictator Bashar Assad and Russian President Vladimir Putin should not underestimate Turkey’s military, a Turkish envoy warned after the United States endorsed the NATO ally’s right to self-defense.

“The regime and its backers are used to killing innocent civilians and members of the opposition for years,” Feridun Sinirlioglu, Turkey’s ambassador to the United Nations, said during an emergency Security Council meeting Friday. “Some warlord in Damascus may not know the difference. Some extremist mercenaries fighting along with the regime may not know the difference. If they want to learn the hard way, they will.”

That threat blurred the distinction between the Assad regime and Russia, although the Turkish envoy avoided accusing the Russian military of direct involvement in the Thursday strike that killed 33 Turkish soldiers in Idlib. U.S. officials closed ranks with Ankara, despite significant recent disputes over the wayward NATO ally’s purchase of Russian anti-aircraft missile defense systems.

“In the days ahead, the United States’s commitment to our NATO ally, Turkey, will not waver. Turkey has our full support to respond in self-defense to unjustified attacks on Turkish observation posts that resulted in the deaths of their own forces,” Kelly Craft, the U.S. ambassador to the U.N., said during the meeting.

“We call for the Russian Federation to immediately ground its warplanes,” she added, "and we call for all Syrian forces and their Russian backers to withdraw to the ceasefire lines first established in 2018.”

Turkey blamed the strike on Syrian forces, but a senior State Department official emphasized that, “as a general rule, there is very close coordination” between the Syrian and Russian militaries. NATO members held an emergency consultation earlier on Friday, but Turkey hasn’t invoked the Article 5 provisions of the NATO treaty that bind the allies to treat an attack on one member as an attack on all.

“We’re working on ways to support the Turks. Again, this will not involve military moves by American units,” the senior State Department official said. “We have taken no decision to engage with U.S. combat units in this conflict. We obviously provide military support of various types to all of our NATO allies all of the time.”