LONDON -- British Prime Minister Liz Truss says the country is "devastated" by the death of Queen Elizabeth II, calling her "the rock on which modern Britain was built."

Watch Truss' remarks in the player above.

Truss said the news is "a huge shock to the nation and to the world" but that the queen's spirit will endure.

Truss was appointed by the queen just two days ago, becoming the 15th prime minister to serve during Elizabeth's reign.

The Union Jack flag atop the prime minister's 10 Downing Street residence was lowered to half-staff after the monarch's death was announced.

Elizabeth died peacefully Thursday afternoon at at Balmoral Castle in Scotland. All four of her children and her grandson Prince William traveled there to be at her side.

Elizabeth was Britain's longest-reigning monarch and a rock of stability across much of a turbulent century. She died Thursday after 70 years on the throne. She was 96.

The palace announced she died at Balmoral Castle, her summer residence in Scotland, where members of the royal family had rushed to her side after her health took a turn for the worse.

A link to the almost-vanished generation that fought World War II, she was the only monarch most Britons have ever known, and her name defines an age: the modern Elizabethan Era.

The impact of her loss will be huge and unpredictable, both for the nation and for the monarchy, an institution she helped stabilize and modernize across decades of huge social change and family scandals.

With the death of the queen, her 73-year-old son Charles automatically becomes monarch, though the coronation might not take place for months.

Tags: Queen Elizabeth II