In pictures: United States observes 17 years of 9/11 attacks
Nearly 3,000 people were killed in the attack perpetrated by the Al-Qaeda.
New York honored the 3,000 killed in the attack
New York on Tuesday honoured the nearly 3,000 people killed on September 11, 2001, in a ceremony at Ground Zero, the site where hijacked Al-Qaeda planes brought down the Twin Towers.
The 17th anniversary of the deadly attack was commemorated in fog and gentle rain by relatives of those who were killed, police officers, firefighters and officials, who remembered what remains the deadliest single attack on US soil.
Americans gathered at the National September 11 Memorial and marked moments of silences at 8:46 am and 9:03 am, the exact times that the passenger jets struck the North and South Towers.
New York Governor Andrew Cuomo, the US ambassador to the United Nations, Nikki Haley and Mayor Bill de Blasio, together with his predecessors, Michael Bloomberg and Rudy Giuliani, were among those who attended.
'Not a day to give speeches, it's about the heart'
'It is not a day to give speeches, it is not a day to talk about politics. It's about the heart,' said Alice Greenwald, director of the 9/11 Memorial Museum.
'We need to stand together, that's the only way we can deal with that kind of pain,' she added.
Victims were remembered
In what has become an annual tradition, relatives began reading out the long list of those who were killed, saying a few words about those who died, in a ceremony that takes longer than three hours.
The New York Stock Exchange also marked a moment of silence at 9:20am and fire stations welcomed relatives of those who were killed. The department suffered a particularly heavy blow, with a total of 343 dead.
'Waves of flags' recalled the tragedy
'Waves of Flags' displayed at Pepperdine University in Malibu, California on September 10, 2018, where the annual display of 2,997 flags commemorates victims of the September 11, 2001 terrorist attacks.
In addition to those killed on September 11, thousands of first responders, construction workers and residents have since developed illness, many of them terminal, as a result of inhaling the toxic fumes.Al-Qaeda hijacked a total of four planes.