President Joe Biden marked the 21st anniversary of the Sept. 11, 2001, attacks on Sunday, attending a somber wreath-laying ceremony at the Pentagon held in steady rain and paying tribute to the “extraordinary Americans” who gave their lives in one from the nation’s darkest days, News.ro reports with reference to the Associated Press.

Sunday’s ceremony came just over a year after Biden ended the long and expensive war in Afghanistan launched by the US and its allies in response to terrorist attacks.

Biden said that even after the United States left Afghanistan, his administration continued to pursue those responsible for the September 11 attacks. Last month, Biden announced that the US had killed Ayman al-Zawahri, the al-Qaeda leader who helped plan the 9/11 attacks, in a covert operation.

“We will never forget, we will never give up,” Biden said. “Our commitment to preventing another attack on the United States is unending.”

The president also recalled the comforting words of Queen Elizabeth II, who died last week, to the American people in the immediate aftermath of the 2001 terrorist attacks: “Pain is the price we pay for love.” Biden said those words remain as moving as they were 21 years ago, but the weight of the loss remains heavy.

“The price seems so high these days,” Biden said.

“It is not enough to defend democracy once a year or from time to time. This is what we must do every day. So this is not only a day of remembrance, it is also a day of renewal and determination for every American in our commitment to this country, to the principles it embodies, to our democracy,” said the US president.

First Lady Jill Biden addressed a crowd outside the Flight 93 National Memorial in Shanksville, Pennsylvania, where she recalled her concern for her sister Bonnie Jacobs, a United Airlines flight attendant.

She said the attacks showed that “with courage and kindness we can be a light in this darkness.”

“It showed us that we’re all connected,” said Jill Biden, who was joined by her sister in Shanksville for Sunday’s celebration. “So as we stand on this sacred and wounded ground, a record of our shared pain and a monument to the memories that live each day, this is the legacy we carry far beyond: Hope that defies hate.”

Vice President Kamala Harris and her husband attended a memorial service at the National September 11 Memorial in New York.