Syrian state television reported late Sunday night that there were explosions heard at the T4 air base outside of Homs and blamed the U.S. for the apparent attack.
Syria's state-run news agency, SANA, later reported that Syrian air defenses had shot down eight Tomahawk missiles.
Several U.S. officials initially said the press reports from Syria about a U.S. missile attack were false.
The Pentagon later issued an official statement denying the reports of airstrikes in Syria.
"At this time, the Department of Defense is not conducting airstrikes in Syria. However, we continue to closely watch the situation and support the ongoing diplomatic efforts to hold those who use chemical weapons, in Syria and otherwise, accountable," said the Pentagon statement.
A U.S. official told ABC News that the U.S. intelligence community is assessing the alleged chemical attack.
The Pentagon's denial followed speculation that the U.S. was considering military action after reports of an apparent chemical attack in the Syrian town of Douma on Saturday that killed dozens of civilians.
It was a year ago this week that Trump ordered Tomahawk missile strikes at a Syrian base in Syria days after a Sarin gas attack by the Assad regime that killed 100 civilians and injured hundreds more.