Speaking from the Rose Garden Wednesday afternoon during a joint press conference with King Abdullah of Jordan, President Trump firmly addressed the chemical weapons attack on civilians yesterday and said the "affront to humanity" crossed a number of lines.

"It crossed a lot of lines with me," Trump said. "That crosses many many lines, beyond a red line."

When pressed by AP reporter Julie Pace, Trump said the Syria problem is now his responsibility which he will carry proudly.

"That attack on children yesterday had a big impact on me, that was a horrible, horrible thing. I've been watching it and seeing it. It doesn't get any worse than that," Trump said. "It is very very possible that my attitude toward Syria and Assad has changed....You're now talking about a whole different level."

President #Trump said the Syrian chemical attack crossed “many, many lines, beyond a red line.” https://t.co/BcYwjNnRJy pic.twitter.com/ACCxoYWZhr — Fox News (@FoxNews) April 5, 2017

Trump's comments signal a major shift in policy. Last week the administration took the position Assad should remain in power. The administration has also argued President Obama's failure to act when his red line of chemical weapons use was crossed in 2013 led to yesterday's attack.

Earlier today, Secretary of Defense James Mattis said Assad's actions were "heinous" and will be "treated as such."

This post has been updated with additional information.