King and Queen lay flowers at 9/11 Memorial in New York

King Charles III and Queen Camilla laid flowers at the September 11 Memorial in New York, in a sombre moment during their state visit to the United States.

It is the first time that the royal couple have been to the site, which remembers the nearly 3,000 people who lost their lives in the attacks of 25 years ago.

They met families of those who died and talked to some of the first responders involved in the rescue attempt, and New York's Mayor Zohran Mamdani and former Mayor Michael Bloomberg were among the dignitaries at the event.

The visit took place amid very tight security, with a heavy police presence, road closures, checkpoints and helicopters circling overhead.

In the New York sunshine, the King and Queen left a bouquet of white roses beside the deep pools that now commemorate those who lost their lives at this spot.

There is a museum on the site, which is now a permanent memorial, in an open space surrounded by the city's skyscrapers.

The King and Queen also had conversations with representatives of charities who have supported the families of victims and educational groups who are preserving the memory of what happened here in 2001.

The importance of the 9/11 attacks had been raised by King Charles in his speech to the US Congress on Tuesday.

He had called on US lawmakers to maintain support for Nato and had given the example of how Nato members had rallied to help the US in the wake of the 9/11 attacks.

"This atrocity was a defining moment for America and your pain and shock were felt around the whole world," said the King.

And he told Congress the "same unyielding resolve is needed for the defence of Ukraine".

The trip to New York, the third day of their four-day visit, will also have a lighter moment.

The Queen, a campaigner for literacy and reading, is bringing her own literary figure to donate to New York Public Library.

Since 1987, the library has had on display the original stuffed toys from the 1920s that inspired the Winnie the Pooh stories.

But since the 1930s, the toy of Roo, the baby kangaroo, has been missing.

A replacement Roo has been brought by the Queen on the flight from the UK, with the toy made by the same firm that made the originals.

The Queen has promoted literacy through her Queen's Reading Room project - and the charity's CEO, Vicki Perrin, who has also travelled to New York, warned on Wednesday that we are in a "reading crisis".

She highlighted the social benefits brought by improving rates of literacy and reaching, which she said had "transformative benefits on mental health, brain health and social health".

Later on Wednesday, the King will go to see an education and healthy food initiative in Harlem.

And the King and Queen will attend a reception for the creative industries, which is expected to attract some famous faces.