Canada proclaimed Charles as its king on Saturday in an official ceremony at the official residence of the governor general in Ottawa, the monarch's representative in Canada who acts as head of state on behalf of the crown, Reuters reported.

Earlier, the Accession Council met at St. James's Palace in London, where Charles was proclaimed sovereign. These ceremonies are protocol and formalize the change of head of state.

Charles, 73, automatically became king of the United Kingdom and head of 14 other kingdoms, including Canada, when his mother, Queen Elizabeth, died Thursday at age 96.

Canada declared a 10-day mourning period for the queen. Although Canada ceased to be a British colony in 1867, it remained part of the British Empire until 1982 and is still a member of the Commonwealth of the Former Empire, whose head of state is a British monarch.

Prime Minister Justin Trudeau and Governor General Mary Simon signed the decree proclaiming the new sovereign after a cabinet meeting.

The trumpets then heralded Canada's chief herald out of the residence. He read the decree proclaiming the new monarch in English and French.