Senior US lawmakers from both parties expressed support for President Donald Trump's ordered military strike on a Syrian air base, but some rank-and-file members warned against further action without congressional authorization.
Trump told the American people he ordered air strikes on Syrian forces in retaliation for a "barbaric" deadly chemical attack on civilians that he blamed on the country's strongman President Bashar al-Assad.
"Making sure Assad knows that when he commits such despicable atrocities he will pay a price is the right thing to do," Senate Minority Leader Chuck Schumer, the country's top Democrat and a frequent critic of the nascent Trump administration, said in a statement.
Republican House Speaker Paul Ryan called the action "appropriate and just," adding that the strikes "make clear that the Assad regime can no longer count on American inaction as it carries out atrocities against the Syrian people."
Senator John McCain, a national security hawk who for years has advocated a more muscular policy against the Syrian regime, hailed the strike as a "credible first step."
"Unlike the previous administration, President Trump confronted a pivotal moment in Syria and took action."
Several lawmakers, including Ryan and Schumer stressed the need for Trump to consult with Congress on forging the appropriate US military strategy against Syria.
Senator Ben Cardin, the ranking Democrat on the Foreign Relations Committee, said the targeted bombings "send a clear signal" of US resolve.
"However, and I cannot emphasize this enough, any longer-term or larger military operation in Syria by the Trump administration will need to be done in consultation with the Congress," he said.
Democratic congressman Adam Schiff is among several lawmakers who have long sought a new, more narrowly defined congressional authorization for US military action in the aftermath of the 9/11 attacks of 2001 and the fight against terrorism.
"I will be re-introducing an authorization for use of military force against ISIS and al-Qaeda when Congress returns to session" after its two-week recess which begins Friday, Schiff said.
Democrat Barbara Lee, part of an anti-war coalition along with some isolationist Republicans who opposed president Barack Obama when he sought approval for intervention in Syria in 2013, was more blunt.
"This is an act of war," she wrote on Twitter.
"Congress needs to come back into session and hold a debate. Anything less is an abdication of our responsibility."
Senate Republican Rand Paul added that "while we all condemn the atrocities in Syria, the United States was not attacked."
Trump "needs congressional authorization for military action as required by the Constitution," he said, adding that intervention in Syria would do "nothing to make us safer."
House Democrat Ted Lieu agreed that Trump needs approval for his military action.
"Congress authorized (the president) to use force on terrorists. We NEVER authorized force to enforce chemical weapons treaty," he tweeted.