Sen. John McCain (R-Ariz.) lambasted Donald Trump on Sunday, saying the President’s remarks on soon withdrawing U.S. troops from Syria “emboldened” the country’s leader Bashar al-Assad to order an alleged chemical weapons assault.

John McCain Blames Trump For ‘Emboldening’ Assad

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The Republican from Arizona, a war veteran who serves as chairman of the Senate Armed Services Committee, has been one of Trump’s most fierce critics among GOP officials since the president took office.

“President Trump last week signaled to the world that the United States would prematurely withdraw from Syria,” McCain 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.”

McCain’s released his statement just hours after a Trump tweet that warned there would be a “big price to pay” for an alleged chemical weapons attack in Syria. The president blamed Russian leader Vladimir Putin’s support of the Syrian regime led by Assad. Trump also slammed his predecessor Barack Obama’s policy decisions in the war-ravaged country.

On Saturday, Syrian activist organizations stated toxic gas inside barrel bombs launched from helicopters over Douma, a suburb of Damascus, left scores of civilians dead and many more injured.

Last year, McCain — a prisoner of war whom Trump once controversially said was “not a war hero” — approved of Trump’s decision to order a missile strike on an airfield in Syria as a response to a previous alleged chemical attack. The Senator urged the President to take a similar course of action this year.

“He should do so again, and demonstrate that Assad will pay a price for his war crimes,” McCain added in his statement.

Nikki Haleythe U.S. Ambassador to the United Nations, stated Sunday that the United States and eight other nations demanded an emergency U.N. Security Council meeting Monday to talk about the crisis.

Multiple legislators responded Sunday to the alleged chemical weapons strike launched by Assad, as well as to Trump’s tweets.

House Speaker Paul Ryan denounced the attack on Twitter, and also advocated for greater punishment to Syria and Russia:

Sen. Chris Murphy (D-Conn.) called Ryan’s words “empty” and urged Congress to utilize its power to authorize greater military responses when it comes to foreign policy.

Nancy Pelosithe House Minority Leader, said in a statement that if confirmed, the chemical attack “would be a war crime of staggering inhumanity.” Pelosi also said “a thorough investigation” was vital.

Sen. Lindsey Graham — who like McCain is one of the Republican Party’s top supporters of greater U.S. involvement in Syria — pushed for an increase in sanctions against Assad.

“To me, I would destroy Assad’s air force,” the South Carolina Senator stated 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.”