In a late-night statement, the White House said the United States discovered "potential preparations for another chemical weapons attack" by the Syrian government.
The statement said the activites are similar to prepartion the "regime made before its April 4, 2017, chemical weapons attack." The US responded to that attack that killed 100 people, including 25 children, by firing 59 Tomahawk cruise missiles at a Syrian airfield that was believed to have carried out the strike on a rebel-held area.
In the statement, the US warned Syria would "pay a heave price" if it proceeds with the attack
"As we have previously stated, the United States is in Syria to eliminate the Islamic State of Iraq and Syria," the White House warned Syria. "If, however, Mr. Assad conducts another mass murder attack using chemical weapons, he and his military will pay a heavy price."
Shortly after the release of the statement, Nikki Haley, the US ambassador to the UN, sent a warning to Iran and Russia that the US would also blame them if Syria proceeds with another chemical attack. "Any further attacks done to the people of Syria will be blamed on Assad, but also on Russia & Iran who support him killing his own people," Haley wrote.
Any further attacks done to the people of Syria will be blamed on Assad, but also on Russia & Iran who support him killing his own people.— Nikki Haley (@nikkihaley) June 27, 2017