Sept. 9 (UPI) -- In his first speech after ascending the British throne, King Charles III on Friday called his mother, Queen Elizabeth II, an inspiration and urged people to remember and draw strength "from the light of her example."
"May flights of angels sing thee to thy rest," Charles said in the speech, delivered via video in London. He pledged the same life-long service to the crown as his mother.
Elizabeth died Thursday at age 96, ending a 70-year reign that was Britain's longest.
"Alongside the grief that all my family are feeling," Charles said, "we also share with so many of you in the United Kingdom, in all the countries where the queen was head of state, in the commonwealth and across the world, a deep sense of gratitude for the more than 70 years in which my mother as queen served the people of so many nations."
Charles declared in the address that his oldest son, Prince William, is now heir apparent and prince of Wales. He also expressed love for his son, Prince Harry and daughter-in-law Meghan Markle, who left their royal duties for independent lives in the United States.
"I want to express my love for Harry and Meghan as they continue to build their lives overseas," Charles said.
Charles' wife, Camilla, becomes his queen consort.
"I know she will will bring to her new role the steadfast devotion to duty on which I have come to rely so much," he said.
Charles paid tribute to his mother's memory and vowed to uphold "the constitutional principles at the heart of our nation."
The king spent the night at the royal family's Balmoral estate in Scotland, where the queen died on Thursday, and departed with Queen Consort Camilla early Friday to return to London.
"My beloved mother was an inspiration and an example to me and all of my family," Charles said to open his address. "And we owe her the most heartfelt debt ... for her love, affection, guidance, understanding and example."
"I have been brought up to cherish a sense of duty to others," he added. "And to hold in the greatest respect the precious traditions, freedoms and responsibilities of our unique history."
The royal family has declared a period of national mourning, which will last for seven days after the queen's state funeral. That funeral date has not yet been set.
Royal officials said Friday that Charles will be proclaimed king by Britain's Accession Council at St. James's Palace on Saturday. Before then, he will also formally be welcomed in London as the new sovereign by members of the Privy Council. The ceremony on Saturday is scheduled for 10 a.m. BST (5 a.m. EDT).
Also Friday, the king will meet privately with British Prime Minister Liz Truss. He and Truss began new roles atop the British government this week. Truss took over for Boris Johnson on Monday.
Flags flying from royal residences, government buildings and military establishments have been lowered to half-mast and will stay that way for at least a week.
Other tributes include royal gun salutes in London on Friday in Hyde Park and at the Tower of London by the Honorable Artillery Company. Ninety-six rounds will be fired -- one for each year of the queen's life.
Buckingham Palace said royal residences will close until after the queen's funeral, including The Queen's Gallery and the Royal Mews at Buckingham Palace and The Queen's Gallery in Edinburgh.
The royal family said that there are no physical Books of Condolence at the Royal Residences, but mourners can write in an online Book of Condolence on the royal family's website.
A service of prayer and reflection for the queen will take place at St. Paul's Cathedral Friday night with space for up to 2,000 mourners.
"We remember with gratitude the life of Her Majesty Queen Elizabeth II," Andrew Tremlett, dean-designate at St. Paul's Cathedral, said according to Sky News. "Over many centuries St. Paul's Cathedral has been a place to remember and mourn the lives of many of those who have died."
"As we join her family and the nation in mourning, we commend her life and work to God."
Mourners have been bringing flowers to several locations to pay tribute to Elizabeth. Flowers and other items have been piling up at Buckingham Palace, the Balmoral castle where the queen died, Windsor Castle, the Palace of Holyroodhouse in Edinburgh and Hillsborough Castle in Northern Ireland.
The royal family said a memorial flower garden will be created in Green Park on Saturday and will be the main location for laying flowers near Buckingham Palace.