President Barack Obama said he made a mistake in making the “totally irresponsible” decision to launch a strike against Syria’s chemical weapons arsenal in 2014, but he said it was the right thing to do.

Obama told CBS’s “Face the Nation” that the U.S. must take a hard line against Syria and its leader, Bashar al-Assad, and that his administration has taken a “more nuanced position” on the conflict in the region.

In 2014, Obama said, he was “extremely disturbed” by Syria’s use of chemical weapons against its own people, a claim that has been repeatedly debunked.

He said the use of the weapons would have been “catastrophic” and led to “terrible humanitarian consequences.”

Obama said in an interview with CBS’s John Dickerson that he was forced to make the “very difficult choice” to launch the chemical weapons attack because of his “very serious concerns” about the use.

“I made a very tough decision, John, because I had serious concerns about the consequences of the use, and the consequences were catastrophic, and I thought that the United States had to take a harder line in this area,” he said.

The president also said that he believed that Syria would never use chemical weapons again, even after the Obama administration imposed strict U.N. sanctions against the Syrian regime in 2013.

“The use of these weapons is something that I don’t think would ever happen again,” Obama said.

Obama made the remarks during a roundtable discussion with the CBS “Face The Nation” host, CBS News chief foreign affairs correspondent Major Garrett and CBS News political correspondent David Martin.