Secretary of State Mike Pompeo says the United States has concluded that the Syrian government used chemical weapons in an attack in May.

Speaking in New York on the sidelines of the U.N. General Assembly on Thursday, Pompeo said U.S. officials had determined that Syrian President Bashar al-Assad’s government had used chlorine in the attack on opposition forces in Idlib province on May 19.
 
He said the U.S. would provide an additional $4.5 million to the Organization for the Prohibition of Chemical Weapons to fund investigations into other instances of suspected Syrian chemical weapons use.

Pompeo also called on the Assad government to release thousands of unjustly detained prisoners, including American journalist Austin Tice. Tice has been missing and presumed held by the government for seven years.