 Complete the following phrase:  The United States government stated it would investigate whether the Syrian government used chemical weapons, as stated, and threatened to respond quickly should the reports be confirmed. The United Kingdom stated that they would respond if any chemical weapons were proven to have been used. The French government said that it had noted the allegations with concern. U.S. Special Envoy for the Syrian conflict, James Franklin Jeffrey, later stated to the United States House of Representatives foreign relations committee that the attack reports could not be confirmed. The U.S., UK, and France had previously launched limited attacks on the Assad government in response to reported chemical attacks in prior years, particularly the 2017 Shayrat missile strike and the 