NEW YORK — President Donald Trump joined the military in observing a moment of silence at the Pentagon for the 18th anniversary of 9/11.

The moment of silence is traditionally observed at 9:37 a.m. - the exact time when a plane crashed into the Defense Department's headquarters on Sept. 11, 2001, killing 184 people. But this year's ceremony ran late, and the anniversary was observed at 9:47 a.m.

The commander in chief told families that "this is your anniversary of personal and permanent loss" and he said that their "loved ones will never ever be forgotten."

When he arrived at the Pentagon, he was greeted by Defense Secretary Mark Esper. The president placed a wreath of red, white and blue flowers at the memorial site.

CBS NEWS reported Trump brought up his canceled Camp David meeting with the Taliban during his speech at the Pentagon.

That such a secret meeting was supposed to take place at Camp David in the first place rattled the president's critics and even some of his allies. Mr. Trump and his administration have been defending both the move to set up the meeting and to cancel it since.

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"I called them off when I learned that they had killed a great American soldier from Puerto Rico..." the president told his audience, claiming the U.S. has been hitting its enemies harder than ever before in the past four days. He added that anyone who dares strike the U.S. will be dealt with gravely. 

Mr. Trump also recalled where he was on that fateful day 18 years ago, sitting at home watching a business television show when "all of the sudden," the screen cut away. The president described the "great confusion," until he watched as a second plane came at "tremendous speed" and crashed into the second World Trade Center Tower. 

"It was then I realized the world was going to change," he said. 

The president said that for every American who lived through that day, "the September 11 attack is seared into our soul."