Hillary Clinton on Sunday said there are “lessons still to be learned” from the Sept. 11, 2001, attacks, noting the country’s unity following the terrorist attacks.

“We have also, I think, been reminded about how important it is to try to deal with extremism of any kind, especially when it uses violence to try to achieve political and ideological goals,” Clinton said during an interview with co-anchor Dana Bash on CNN’s “State of the Union” on the 21st anniversary of the attacks.

“So I’m one who thinks that there are lessons still to be learned from what happened to us on 9/11 that we should be very aware of, during this time in our country and the world’s history.”

President Biden, Vice President Harris and other senior officials traveled to remembrance ceremonies at the World Trade Center and Pentagon on Sunday morning.

Clinton at the time of the attacks served as a U.S. senator from New York and years later served as secretary of State during the Obama administration, managing the country’s foreign policy during U.S. interventions in the Middle East spurred by the attacks.

The ex-first lady reflected on the country’s response to the attacks on CNN, lauding former President George W. Bush’s commitment to helping rebuild New York after the collapse of the Twin Towers.

“I feel grateful that we were able to come together as a country at that really terrible time,” Clinton said. “We put aside differences. I wish we could find ways of doing that again.”

She added that she hopes the country could unite again, touting Biden’s legislative record on issues like climate change, health care and gun violence.

“We are in a funny position, Dana, because there’s a small but very vocal, very powerful, very determined minority who wants to impose their views on all the rest of us,” Clinton told Bash.

“And it’s time for everybody regardless of party to say, no, that’s not who we are as America,” Clinton added.