US marks 22 years since 9/11 from ground zero to Alaska

Americans are looking back on the horror and legacy of 9/11, gathering on Monday at memorials, firehouses, city halls and elsewhere to observe the 22nd anniversary of the deadliest terror attack on US soil.

Commemorations stretch from the attack sites - at New York's World Trade Centre, the Pentagon and Shanksville, Pennsylvania - to Alaska and beyond. President Joe Biden is due at at a ceremony on a military base in Anchorage.

His visit, en route to Washington from a trip to India and Vietnam, is a reminder that the impact of 9/11 was felt in every corner of America, however remote. The hijacked plane attacks claimed nearly 3000 lives and reshaped American foreign policy and domestic fears.

Communities across the US will pay tribute with moments of silence, tolling bells, candlelight vigils and other activities. In Columbus, Indiana, 911 dispatchers broadcast a remembrance message to police, fire and EMS radios throughout the 50,000-person city, which also holds a public memorial ceremony.

Boy Scouts and Girl Scouts raise and lower the flag at a commemoration in Fenton, Missouri, where a Heroes Memorial includes a piece of World Trade Centre steel and a plaque honouring 9/11 victim Jessica Leigh Sachs. Some of her relatives live in the St. Louis suburb of 4000 residents.

"We're just a little bitty community," said Mayor Joe Maurath, but "it's important for us to continue to remember these events. Not just 9/11, but all of the events that make us free."

As another way of marking the anniversary, many Americans do volunteer work on what Congress has designated both Patriot Day and a National Day of Service and Remembrance.

At ground zero, Vice President Kamala Harris is due to join the ceremony on the National September 11 Memorial and Museum plaza. The event will not feature remarks from political figures, instead giving the podium to victims' relatives for an hourslong reading of the names of the dead.

James Giaccone signed up to read again this year in memory of his brother, Joseph Giaccone, 43. The family attends the ceremony every year to hear Joseph's name.

"If their name is spoken out loud, they don't disappear," he said.

The commemoration is crucial to him.

"I hope I never see the day when they minimise this. It's a day that changed history."

Biden, a Democrat, will be the first president to commemorate September 11 in Alaska, or anywhere in the western US. He and his predecessors have gone to one or another of the attack sites in most years, though Republican George W. Bush and Democrat Barack Obama each marked the anniversary on the White House lawn at times. Obama followed one of those observances by recognising the military with a visit to Fort Meade in Maryland.

First lady Jill Biden is due to lay a wreath at the 9/11 memorial at the Pentagon.

In Pennsylvania, where one of the hijacked jets crashed after passengers tried to storm the cockpit, a remembrance and wreath-laying is scheduled at the Flight 93 National Memorial in Stoystown operated by the National Park Service. Harris' husband, Doug Emhoff, is expected to attend the ceremony.

The memorial site will offer a new educational video, virtual tour and other materials for teachers to use in classrooms. Educators with a total of more than 10,000 students have registered for access to the free National Day of Learning program, which will be available through the fall, organisers say.

"We need to get the word out to the next generation," said memorial spokesperson Katherine Hostetler, a National Park Service ranger.