WASHINGTON – The lives of American troops in Syria to fight the Islamic State may have just gotten more dangerous, with President Donald Trump’s missile strikes potentially making them the targets of the Syrian military as well.

“Hopefully that was in the forefront of the president’s and his military commanders’ minds when they decided to do this,” said Luke Hartig, a former senior director for counterterrorism at the National Security Council under former President Barack Obama.

The dozens of cruise missiles launched into Syria on Thursday night also mark the latest military escalation by a commander-in-chief who had promised fewer such engagements, not more of them, on the campaign trail.

Since taking office 11 weeks ago, Trump has ramped up military involvement in Yemen, Iraq and Syria. In Yemen, where the United States previously had little presence, he expanded a bombing campaign after a botched special forces raid ended in the death of a Navy SEAL and dozens of civilians. Meanwhile, troop levels in both Iraq and Syria have increased as well.

All this occurred under the rubric of fighting terrorism ― that is, until Thursday night, when Navy destroyers fired 59 cruise missiles at a Syrian military base from which U.S. officials believe the Syrian regime launched a chemical weapons attack that killed at least 87 civilians in Idlib on Tuesday.

“It was aimed at this particular airfield for a reason ― because we could trace this murderous act back to that facility,” National Security Adviser H.R. McMaster told reporters late on Thursday.

Now, U.S. service members in Syria as part of the campaign to defeat ISIS may face new threats from Syrian leader Bashar Assad’s forces, which are backed by Russia.

“Whether this leads Syria to escalate things, whether this leads Russia to escalate things, we just don’t know,” Hartig said. “We’re still waiting to see how the dust settles.”

Whether this leads Syria to escalate things, whether this leads Russia to escalate things, we just don’t know. Luke Hartig, former National Security Council official

It’s not clear exactly how many U.S. service members are currently in Syria. The Department of Defense was floating a plan to deploy 1,000 troops last month, adding to the roughly 1,000 already there to help Syrian rebels attack the ISIS stronghold of Raqqa. Most of these troops are stationed far from Assad’s military, which does not have much of a presence in the northeastern part of the country.

It’s also unknown whether Assad would directly attack U.S. troops when his primary concern is defeating an insurgency trying to overthrow him. Doing so could wind up leading to his ouster and potential arrest for war crimes.

In any event, the fragile dialogue between U.S. and Russian forces in Syria to avoid inadvertent conflicts has collapsed. Russia announced it was suspending the “de-confliction channel” established under Obama to enable communication between Russian and American battlefield commanders.

Trump scolded Obama in 2013 for considering military strikes against Assad for using chemical weapons, arguing that it was a bad idea to get involved in Syria’s civil war. Obama had pushed for strikes on dozens of targets, not just one, but decided against them when both Republicans and Democrats in Congress expressed opposition.

Trump’s anti-interventionist attitude toward Syria continued throughout his campaign for president, when he repeatedly said that as bad as Assad was, ISIS was worse. He also said he would try to cooperate with Russia and possibly Assad in the fight against the terrorist group.

As late as last week, the U.S. was signaling that it was not interested in Assad. Secretary of State Rex Tillerson, traveling in Turkey, said Assad’s fate “will be decided by the Syrian people.”

But faced with the televised images of children who had died in Idlib, Trump ― who is known to get much of his information about world affairs from cable news ― reversed course. On Wednesday, he called the civilian deaths “an affront to humanity,” saying, “These heinous actions by the Assad regime cannot be tolerated.”

The Trump administration has not definitely said what it will do next. In the aftermath of the missile strikes, a Department of Defense official told Reuters there are no plans for additional attacks against Assad’s forces. But Trump’s national security adviser, speaking with reporters at Trump’s resort in Palm Beach, Florida, said Assad should take note of what happened.

“This was not a small strike,” McMaster said. “What it does communicate is a big shift, a big shift in Assad’s calculus.”