The Queen has said the UK has been "resolute in the face of adversity" following recent tragedies in London and Manchester.
In a statement released on her official birthday, she said it was "difficult to escape a very sombre mood" in the country.
The Queen visited west London along with the Duke of Cambridge on Friday to visit victims of the deadly fire at the Grenfell Tower.
In her statement, Queen Elizabeth II: "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."
The monarch visited the Royal Manchester Children's Hospital following the Manchester Arena attack in which 22 people were killed following an Ariana Grande concert.
She added: "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."