An aerial attack on Syria’s Idlib province that left at least 80 dead and 200 injured on Tuesday morning was confirmed this morning to have included the use of chemical weapons, Al Jazeera reports. 

“Autopsies were carried out on three of the bodies after they were brought from Idlib,” Turkey’s Justice Minister Bekir Bozdag told a local news agency. “The results of the autopsy confirms that chemical weapons were used.” 

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This marks the second largest chemical weapon attack in Syria’s history, according to the UN. The largest took place in 2013, in Ghouta, killing anywhere from 281 to as many as 1,500 people, according to reports.   

On Tuesday, hours after the attack, the United States, France, and the United Kingdom presented a draft resolution to the UN Security Council calling for a full-scale investigation to be launched. 

US Ambassador to the UN Nikki Haley also warned the UN that the US would take unilateral action on Syria if the international governing body fails to come up with an appropriate response. 

“When the United Nations consistently fails in its duty to act collectively, there are times in the life of states that we are compelled to take our own action,” Haley said. 

She was joined in her call to action by French ambassador to the UN, François Delattre. “Action by the Security Council would be by far the best option,” Delattre said. 

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US President Donald Trump also responded to the attack during a press conference with the King of Jordan on Wednesday: “[The attack] crossed a lot of lines for me. When you kill innocent children, innocent babies, babies, little babies, with a chemical gas that is so lethal – people were shocked to hear what gas it was. That crosses many, many lines, beyond a red line, many, many lines.”

Trump told reporters that the attacks changed his opinion on the Assad regime, and that “all options are on the table” in terms of a US response to the incident.  

US Secretary of State Rex Tillerson cast blame on Russia and Iran in a statement Tuesday: 

BREAKING: Tillerson says Russia, Iran bear 'great moral responsibility' for deaths in Syria from chemical weapons attack.

— The Associated Press (@AP) April 4, 2017

But Russia has denied involvement in the attack, and has claimed that a government shell hit a rebel-held building that was producing chemical weapons, according to the report by Al Jazeera. 

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Along with killing more than 80, the chemical attack induced a range of physical reactions, including, “respiratory problems, vomiting, fainting and foaming at the mouth, and miosis (pupillary constriction),” the UN reports. 

Human rights activist Nadia Murad appealed to her followers with an impassioned call to action: 

Genocide, enslavement, mass killing, war crimes, crimes against humanity, use of chemical weapons?What`s next? SAVE people in Syria and Iraq

— Nadia Murad (@NadiaMuradBasee) April 5, 2017

But bombings of rebel-held areas continued into Wednesday, according to a monitoring site cited by Al Jazeera, with airstrikes killing an additional 27 people in the Idlib province, including 13 children.