Washington (CNN)Republican Sen. John McCain said Sunday that President Donald Trump's comments that the US military would leave Syria "very soon" had emboldened Syrian leader Bashar al-Assad, resulting in the reported chemical weapons attack Saturday that killed dozens of the country's civilians.
Trump: Putin, Iran responsible for backing Assad 01:16
"President Trump last week signaled to the world that the United States would prematurely withdraw from Syria," the Arizona senator said in a statement. "Bashar Assad and his Russian and Iranian backers have heard him, and emboldened by American inaction, Assad has reportedly launched another chemical attack against innocent men, women and children, this time in Douma."
The statement from the hawkish chairman of the Senate Armed Services Committee came hours after Trump tweeted that there would be a "big price to pay" for an alleged chemical weapons attack in Syria. Trump's tweets pinned blame for the situation there on Russian President Vladimir Putin's support for Assad and former US President Barack Obama's past policy in the war-torn nation.
Syrian activist groups on Saturday said toxic gas inside barrel bombs dropped from helicopters over a rebel-held city in Syria killed dozens of civilians and wounded scores more. Syrian state news said an "official source" denied the allegations.
McCain approved of Trump's decision last year to launch a missile strike on a Syrian airfield in response to another alleged chemical weapons attack and called on the President to do the same this year.
"He should do so again, and demonstrate that Assad will pay a price for his war crimes," his statement said.
In a nod to Trump's disapproval of Obama, McCain also said Trump had "inherited bad options after years of inaction by his predecessor."
Trump said late last month that the US would "be coming out of Syria like very soon," although a top general said Thursday that Trump had not yet given a timeline for such a move.
Lawmakers sound off
Several lawmakers reacted Sunday to the alleged use of chemical weapons by Assad's forces and the President's tweets.
House Speaker Paul Ryan issued a statement on Twitter condemning the attack and calling for the US to lead "an international effort to hold the Assad regime and Russia accountable for their actions."
Democratic Sen. Chris Murphy, of Connecticut, took issue with Ryan's tweet as overly vague and said Congress must exercise its power to authorize war.
"I have no idea what this means," Murphy tweeted in response to Ryan. "These are the kind of empty words that makes Congress irrelevant on foreign policy."
"The chemical attacks ARE horrible. But if you support military action, then Congress needs to authorize it," he added. "Just continuing tacit congressional support for existing policy -- more unauthorized troops but zero diplomatic or humanitarian strategy -- is part of the problem."
House Minority Leader Nancy Pelosi said in a statement that the attack, if confirmed, "would be a war crime of staggering inhumanity." She called for international unity and "a thorough investigation," adding that members of Congress expected a comprehensive briefing on the matter.
Republican Sen. Lindsey Graham, who along with McCain is one of the GOP's leading proponents of further US intervention in Syria, advocated for a significant ramp up in anti-Assad actions.
"To me, I would destroy Assad's air force," the South Carolina Republican said on ABC's "This Week." "I would create safe zones in Syria where people can come back to their country from the surrounding area and live a better life. Train up Syrians to take on Assad so we can negotiate in Geneva from a position of strength."
Graham called on the President to "follow through with that tweet," claiming inaction would weaken the United States' hand on the international stage.
Maine GOP Sen. Susan Collins called the attack "horrific" in an interview on CNN's "State of the Union" Sunday morning, adding that Trump would have to rethink his stated desire to withdraw from Syria.
"The President is going to have to reconsider his plan for an early withdrawal in light of what has happened," Collins said.