Queen Elizabeth used her annual birthday speech to reflect on the UK's "very sombre national mood".
The British monarch paid tribute to the victims of the recent "terrible tragedies" - including the terror attacks in Manchester and London and the devastating fire at London's Grenfell Tower - and praised the country for being "resolute in the face of adversity".
She wrote: "Today is traditionally a day of celebration. This year, however, it is difficult to escape a very sombre national mood. In recent months, the country has witnessed a succession of terrible tragedies.
"As a nation, we continue to reflect and pray for all those who have been directly affected by these events. During recent visits in Manchester and London, I have been profoundly struck by the immediate inclination of people throughout the country to offer comfort and support to those in desperate need.
"Put to the test, the United Kingdom has been resolute in the face of adversity. United in our sadness, we are equally determined, without fear or favour, to support all those rebuilding lives so horribly affected by injury and loss."
Queen Elizabeth attended the annual Trooping the Colour ceremony with her family by her side including Prince Philip, Prince Charles, Duchess Camilla, Prince William, Prince Harry and Duchess Catherine.
However, it was the Duke and Duchess of Cambridge's children - Prince George and Princess Charlotte - who stole the show, waving to the crowd and the planes as the flyover took place.
Before the event, the Queen led a one minute silence for the victims of the Grenfell Tower blaze.
The ceremony finished with a procession down Horseguards Parade, with Queen Elizabeth and Prince Philip's carriage leading the parade followed by Prince Harry, Duchess Kate and Camilla following in the second carriage. Prince William and Prince Charles rode on horseback, leading their regiments.