September 11 terrorist attacks: Is there a moment of silence in the UK as US remembers?

3,000 people were killed following the hijacking of four passenger planes in which terrorists crashed into the twin towers at the World Trade Centre in New York, the Pentagon and a field in Pennsylvania on September 11 2001. 

The horrifying and tragic events shook and saddened the United States and the rest of the world. 

The sombre date continues to be marked at Ground Zero, across the United States and is observed in other countries, including the UK too.

A memorial flag brought on stage at the 20th anniversary of the September 11 attacks (Image: AP/PA)

United States marks September 11 terrorist attacks 21st anniversary

President Joe Biden is expected to speak and lay a wreath at the Pentagon on Sunday. 

The First Lady, Dr Jill Biden plans to make a speech in Shanksville in Pennsylvania.

Shanksville is where one of the hijacked planes crashed after passengers and crew members stormed the cockpit which was headed for Washington.

Meanwhile, Vice President Kamala Harris and her husband Doug Emhoff are due at the National September 11 Memorial in New York.

By tradition, no political figures speak at the ground zero ceremony.

Tributes at the National September 11 Memorial & Museum. (Image: John Minchillo/AP/PA)

The solemn occasion centres instead on victims’ relatives who read aloud the names of the dead.

Personal remarks and poignant memories are often added by readers expressing an appreciation for first responders, their love, grief and anger for the loved ones they lost as well as hopes for peace.

Other communities around the country will be marking the day with candlelight vigils, interfaith services and other commemorations.

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Some Americans will join volunteer projects on a day that is federally recognised as both Patriot Day and a National Day of Service and Remembrance.

This year's remembrance event follows a difficult 20th anniversary which was observed just weeks after the US withdrew forces from Afghanistan - a war that the country launched in response to the terrorist attacks two decades before.

President Joe Biden. (Image: PA)

How can you watch the memorials in the UK?

If you would like to watch the memorial services taking place in New York and Pennsylvania, you will be able to live stream the events.

Major broadcasters including NBC News, CNBC, ABC News, CBS News and many others have live streamed the 9/11 commemorations on their YouTube channels in the past.

It is understood that the observances will be aired through the "Watch Live" section of the 9/11 Memorial & Museum website.

Is a 9/11 silence observed in the UK?

There is not an official moment of silence for the September 11 terrorist attacks in the UK.

However, many people choose to take a quiet moment to mark the tragic occasion on the anniversary.

This tends to take place at the same time the first plane hit the Twin Towers at 1.46 pm.