President Trump is promising to act forcefully over what he says was an atrocious use of chemical weapons by the Syrian government. The Syrian regime is accused of using a chlorine agent over the weekend in the town of Douma, just outside Damascus in the battered eastern Ghouta suburbs. More than 40 people were reportedly killed.

The president has said a decision on the U.S. response is imminent, and he is considering holding Syria's allies Iran and Russia accountable.

"We can't let that happen. In our world, we can't let that happen. Especially when we're able to -- because of the power of the United States, because of the power of our country, we're able to stop it," Mr. Trump said.

President Trump has called the suspected chlorine gas attack "barbaric," referencing images of sick, suffocating and dying children. The president has made it clear that all options are "on the table," including a military strike, reports CBS News correspondent Seth Doane from Chtaura, Lebanon, a few miles from the Syrian border .

The Russian Ministry of Defense released a video Tuesday purportedly showing its own military's investigation into the attack. The ministry claims to have found no trace of poisonous substances. Moscow has dismissed the allegations of a chemical attack as "fake news."

Following last year's use of the internationally-banned sarin nerve agent in the Syrian town of Khan Sheikhoun, the Trump administration struck Syria's military with dozens of Tomahawk cruise missiles.

While the Syrian regime has been repeatedly accused of using chlorine as a weapon, it has not yet prompted a military response from the Trump administration.

A strike from the U.S. would set a new precedent and could risk escalating tensions with Iran and Russia, whose U.N. ambassador warned of "grave repercussions" if the U.S. does take military action.