United States President Donald Trump is expected to make a decision by Tuesday on the “forceful” action his military will take against the suspected chemical attack in suburban Damascus in Syria on Saturday.

“We cannot allow atrocities like that. Cannot allow it,” Trump told reporters on Monday during a Cabinet meeting, according to CNN. “If it’s Russia, if it’s Syria, if it’s Iran, if it’s all of them together, we’ll figure it out and we’ll know the answers quite soon.”

Rescue workers said at least 70 people were killed in the attack, but the toll will rise as they get access to the basements where civilians sought refuge from the attack. They added that many of the injured showed symptoms indicating that they were exposed to a compound containing nerve gas.

Both Syria and Russia, its biggest supporter, have denied involvement in the attack in the rebel-held Douma town, instead claiming that rebel groups had fabricated it to thwart the advances of the Syrian troops and provoke global military intervention.

The US president met senior military officers and national security officials on Monday evening, The New York Times reported. While it is not clear how the US will make Syria and its allies “pay a price” for civilian deaths, Trump’s statement indicated that he held Russian President Vladimir Putin responsible for the suspected chemical attack for his association with Syria. Trump is assumed to have close ties with Putin.

Trump has discussed the matter with French President Emmanuel Macron, and both expressed that they will come up with a “firm response”. British Prime Minister Theresa May also called for action against Syrian President Bashar al-Assad and his supporters for the “barbaric” attack, the BBC reported.

The Western leaders made the statements after an emergency meeting of the United States Security Council on Monday. At the meeting, US Ambassador to the UN Nikki Haley said Russia had the “blood of Syrian children” on its hands. She also called for a vote on Tuesday on a draft resolution for a fresh investigation into the use of chemical weapons in Syria. Russian representative Vassily Nebenzia rejected the idea saying it contained “unacceptable elements”, and warned the US of “grave repercussions” if it took military action.