Speaking on CNN's "At This Hour" with Kate Bolduan, the Kentucky lawmaker told the host that he didn't think the Syrian leader launched the attack, and that further intervention by the US government may aggravate the situation.
"Frankly, I don't think Assad would have done that," Massie said. "It does not serve his interests."
Dozens of people -- including at least 10 children -- died, and more than 200 people were injured in a suspected chemical weapons attack
in northern Syria Tuesday. Activist groups and some US officials
have attributed the tragedy to Assad and his regime, including President Donald Trump who cited Assad's administration Wednesday.
When a visibly stunned Bolduan pressed Massie on who -- if not Assad -- may be responsible for the attack, Massie seemed to suggest that the incident could have been unintentional.
"You've got a war going on over there," Massie said. "Supposedly that airstrike was on an ammo dump, and so I don't know if it was released because there was gas stored in the ammo dump or not -- that's plausible."
Massie, who voted against Syrian intervention in 2014, repeated his past statements that US involvement may exacerbate the conflict, citing uncertainty of the reality of the situation.
"We might end up making the situation worse if we launch airstrikes," Massie said. "The first casualty of war is the truth, and it's hard to know exactly what's happening in Syria right now."
When asked about President Donald Trump's blame of former President Barack Obama for the attack, Massie would not assign culpability to the former administration.
"He's gone," Massie said. "It's ours to deal with now."
Some Republicans -- including Trump -- have also called out Assad.
"These heinous actions by the Assad regime cannot be tolerated," Trump said at a Rose Garden news conference. "The United States stands with our allies across the globe to condemn this horrific attack and all other horrific attacks, for that matter."
Appearing on CNN's "New Day" Tuesday
, Arizona Republican Sen. John McCain said the event may been connected to recent indications by the Trump administration
that they will prioritize combating ISIS over removing Assad from power.
"Bashar Assad and his friends, the Russians, take note of what Americans say," McCain said. "I'm sure they took note of what our Secretary of State (Rex Tillerson) said just the other day, that the Syrian people would be determining their own future themselves -- one of the more incredible statements I've ever heard."
When Bolduan played footage of McCain's comments for Massie, the congressman called his Republican colleague "wrong."
"With all due respect to the senator from Arizona, he's wrong," Massie said. "He's not expressing the will of the American people."