Washington — The Pentagon on Tuesday said it detected "active preparations" by Syria for a chemical weapons attack, giving weight to a White House statement hours earlier that the Syrian government would "pay a heavy price" if it carried out such an attack.
A Pentagon spokesperson, Navy Captain Jeff Davis, said the US had seen "activity" at Shayrat airfield that "indicated active preparations for chemical weapons use".
That is the same base from which the Syria air force launched an attack in April that the US and others said used lethal chemicals to kill civilians. Syria denied the charge.
President Bashar Assad's government and Russia dismissed the White House allegation that Damascus was preparing a new chemical weapons attack.
Russian President Vladimir Putin's spokesperson Dmitry Peskov said that "such threats to Syria's legitimate leaders are unacceptable".
Russia is Assad's key backer and sided with him when he denied responsibility for a chemical weapons attack that killed dozens of people in Idlib province on April 4.
The US responded to that attack by hitting the airfield with dozens of cruise missiles.
A Monday evening statement by White House Press Secretary Sean Spicer said the US had "identified potential preparations for another chemical weapons attack by the Assad regime that would likely result in the mass murder of civilians, including innocent children".
Spicer said the activities were similar to preparations taken before the attack in April, but provided no evidence or further explanation.