Washington (CNN) The US has not ruled out launching airstrikes against Syrian President Bashar al-Assad's regime in response to the weekend's suspected chemical gas attack on civilians, Defense Secretary James Mattis said Monday.

"I don't rule out anything right now," Mattis said while hosting Sheikh Tamim Bin Hamad Al-Thani, the emir of Qatar, at the Pentagon.

"The first thing we have to look at is why are chemical weapons still being used at all when Russia was the framework guarantor of removing all chemical weapons, and so working with our allies and partners from NATO to Qatar and elsewhere we are going to address this issue," Mattis continued.

President Donald Trump strongly condemned the "atrocious" chemical weapons attack in Syria during a Cabinet meeting at the White House Monday and said a decision on US action would be made over the next 24-48 hours.

"I'd like to begin by condemning the heinous attack on innocent Syrians with banned chemical weapons," he said. "It was an atrocious attack, it was horrible, you don't see things like that as bad as the news is around the world, you just don't see those images."

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