WASHINGTON — A somber-sounding President Donald Trump recalled "a moment when America fought back" in remarks commemorating the passengers and crew who stormed the cockpit of United Airlines Flight 93, forcing hijackers to crash the plane in a field in Shanksville, Pennsylvania, during the Sept. 11, 2001, terrorist assault on the U.S.

Speaking Tuesday at the Flight 93 memorial, Trump mixed promises to defend America from terrorism with praise for those who foiled the prong of al Qaeda's attack that planners said was intended to strike the U.S. Capitol and sympathetic sentiments for and about their survivors. Specifically, he told the heart-wrenching story of Dorothy Garcia, who asked investigators to retrieve her husband Andrew's wedding ring from the field — a speck-in-the-wreckage mission — and miraculously received it two months later. The telltale inscription: "All my love, 8-2-69" — their wedding date.

It was a notably subdued Trump who spoke 17 years after the terrorist attacks that felled the twin towers of the World Trade Center, damaged the Pentagon and claimed nearly 3,000 American lives. His mien was markedly different from his tone on Twitter Tuesday morning, when he sent messages suggesting the Justice Department has unfairly targeted him with its Russia probe and is not doing enough to go after officials he believes acted against him during the 2016 election.

The passengers and crew members of Flight 93 "rose up, defied the enemy, took control of their destiny and changed the course of history," Trump said. "A band of brave patriots turned the tide on our nation’s enemies and joined the immortal ranks of our nation’s heroes."

Just before 9:30 a.m. on that day, passengers and crew members used airfones to report that their plane had been hijacked and found out about the attacks in New York and Washington. They voted to try to overtake the hijackers and pushed their way into the cockpit. Rather than lose control of the plane, the hijacker pilot downed it, killing all 44 people aboard, including the terrorists.

"They attacked the enemy, they fought until the very end, and they stopped the forces of terror and defeated this wicked, horrible, evil plan," Trump said.

His remarks were all but devoid of politics, though he promised to "never flinch in the face of evil and to do whatever it takes to keep America safe," emphasizing the final three words, which he and his aides often used in describing the intent of a travel ban policy that critics said was aimed at limiting the ability of Muslims to enter the U.S.