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.

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"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.

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