Dozens of victims from the dawn attack April 4 on the northwestern town of Khan Sheikhoun were rushed to Turkish hospitals for treatment after local clinics were also targeted, according to medics and observers at the scene. At least 86 people have died and scores of others were wounded when suspected regime aircraft struck the rebel-controlled town in Idlib province.

In a late-breaking development, CNN has quoted unnamed sources as saying that US President Donald Trump is weighing military action against the regime of President Bashar al-Assad. Responding to the reports, Turkey's President Recep Tayyip Erdogan said he hoped Trump would match his words with action, adding, "Turkey is ready to do everything it can."

Officials from the World Health Organization and the Organization for the Prohibition of Chemical Weapons were present at the examinations of the bodies of three victims who died after reaching Turkey. Turkish Health Minister Recep Akdag said samples would be sent to The Hague for further analysis.

“It was determined that a chemical weapon was used very clearly,” Turkish Justice Minister Bekir Bozdag told the Turkish press.

Autopsies of victims of a crippling assault in northwestern Syria show they were exposed to chemical agents , Turkey revealed on April 6. Calls are growing for action against the Syrian regime, which is being held responsible for the deaths.

The attacks, which left victims foaming at the mouth and writhing convulsively, recalled chilling images of victims of the 2013 sarin attack on Ghouta, a rebel-held suburb of Damascus.

That assault provoked threats of US retaliation, forcing Assad to make a show of abandoning his chemical weapons program to avert an intervention. Syria continues to deny that it is using nerve agents. Speaking at a news conference April 4, Syrian Foreign Minister Walid Moallem said Syrian air force jets had targeted an opposition arms depot that stored chemical weapons. The United Nations says it will investigate the incident as a possible war crime.

Turkey has long lobbied the United States to act decisively to topple the “murderous” Assad regime, but its appeals have fallen on deaf ears. “The chemical attack in Idlib by the Assad regime is a war crime and a crime against humanity,” said Turkey's presidential spokesman Ibrahim Kalin in a tweet. “Shame on those who keep failing the Syrian people.”

Turkey’s ruling Justice and Development Party (AKP) has not forgiven the Barack Obama administration for sending early signals that it was ready to intervene, authorizing the CIA to arm and train rebels, only to get cold feet after the 2012 attack by Islamic militants on the US Consulate in Benghazi that cost US Ambassador Chris Stevens his life.

The Trump administration much like its predecessors has made it clear that its overarching priority in Syria is not regime change but to defeat the Islamic State and al-Qaeda-linked groups that control much of Idlib.

In a much overlooked irony, former Foreign Minister Ahmet Davutoglu, who is largely blamed for Turkey’s bumbling Syria policy, had pleaded with then-Secretary of State Hillary Clinton to be given more time to reason with Assad. His pleas were ignored and Obama declared Assad illegitimate even before Turkey, who subsequently became the rebels’ biggest champion.

But Ankara’s support came at a heavy price. Seized by a determination to overthrow Assad, the AKP turned a blind eye as jihadis including IS fighters used Turkey as a conduit and hijacked the Syrian revolution. Perceived Turkish indulgence of extremists drew sharp rebukes from Turkey’s Western allies and sullied its global image.

The policy also deepened existing fissures between the government’s pious Sunni base and Turkey’s large population of Alevi Muslims who view the AKP and its Syrian rebel proxies as a threat to secularism. Unsurprisingly, the leader of Turkey’s main opposition Republican People's Party, Kemal Kilicdaroglu, has not uttered a single word of sympathy for the victims of Khan Sheikhoun. Turkey’s pro-secular and left-wing opposition press gave the massacre scant coverage.

But the attack on Khan Sheikhoun may have a game-changing effect. The top UN humanitarian official in Syria, Jan Egeland, called the attack a possible “watershed moment.”

Trump told reporters, “I will tell you that attack on children yesterday had a big impact on me," and "My attitude towards Syria and Assad has changed very much.” He added, "It crossed a lot of red lines for me."

Some analysts believe the president’s comments signal a shift in US policy.

But after five years of constant disappointment, the Syrian opposition is not holding its breath. Mohammed Ghanem, a spokesman for the Syrian American Council, told Al-Monitor, “We cannot allow ourselves to become too optimistic. Yes there is a change in tone; yes it’s positive. But we need to be careful.”

Gonul Tol, the executive director of the Turkey program at the Middle East Institute, urges caution as well. She told Al-Monitor, “A symbolic strike against the Assad regime will not substantively alter the situation on the ground. Conversely, decisive action would trigger an exodus of jihadist fighters from Idlib to Turkey and to [Turkish-controlled] Jarablus.”

Either way, the crisis in Syria will remain a huge challenge for Turkey, which has paid the heaviest price for the conflict second only to the Syrian people themselves.