US confirms Assad regime used chlorine in May chemical attack on Syria's Idlib

The United States has confirmed that Syrian President Bashar al-Assad's forces used chemical weapons in May, Secretary of State Mike Pompeo said Thursday, vowing a response.

The Assad regime used chlorine on 19 May as part of its deadly offensive to retake Syria's northwestern Idlib province, Pompeo said.

"The United States will not allow these attacks to go unchallenged nor will we tolerate those who choose to conceal these atrocities," Pompeo told reporters.

"The United States will continue to pressure the insidious Assad regime to end the violence directed at Syrian civilians and participate in the UN-led political process," he said.

The United States had earlier said that it suspected the chemical weapons attack but had held off on making a clear determination.

The Russia-backed Assad regime has repeatedly used chemical weapons against civilian targets over the course of the brutal civil war, international investigators have said.

Former President Barack Obama had called chemical weapons use a red line but ultimately rejected military retaliation against the regime after its 2013 chemical attack on the Damascus suburb Ghouta, which killed as many as 1,729 people.

Current US President Donald Trump ordered strikes on a regime airbase with 59 cruise missiles in response to a sarin gas attack in April 2017.

The gas attack hit the town of Khan Sheikhoun in Idlib, since retaken by pro-regime troops this year.

Pompeo declined to specify what further responses were planned with regards to the 19 May attack.

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