September 27, 2019 - 14:07 AMT
U.S. accuses Assad of chemical attack in Syria's Idlib

The United States has concluded that Syrian President Bashar al-Assad's forces used chemical weapons in an attack in May, Secretary of State Mike Pompeo has said, vowing a response, Al Jazeera reports.

The Assad regime used chlorine on May 19 as part of its deadly offensive in the last rebel stronghold of Idlib, Pompeo said on Thursday at a news conference in New York, where he has been attending the United Nations General Assembly.

"The Assad regime is responsible for innumerable atrocities some of which rise to the level of war crimes and crimes against humanity," Pompeo told reporters.

"The U.S. will not allow these attacks to go unchallenged nor will we tolerate those who choose to conceal these atrocities."

Pompeo added that the U.S. would continue to pressure the Assad regime to end the violence and participate in the United Nations-led political process.

The U.S. said in May it had received numerous reports that appeared consistent with chemical exposure after an attack by Syrian government forces in northwest Syria, but it had made no definitive conclusion as to whether they used chemical weapons.