US President Joe Biden has confirmed he is planning to attend the Queen's funeral when it takes place in the UK.
While no formal plans for Her Majesty's funeral have been announced yet, the ceremony is expected to take place within 10 days after her death.
The 96-year-old monarch died on Thursday at her home in Balmoral, Scotland, surrounded by members of the Royal Family.
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Tributes to the sovereign have flooded in from around the world, including Mr Biden, who described her as a "stateswoman of unmatched dignity and constancy".
Speaking to reporters as he boarded Air Force One on Friday, the president said that he plans to attend the funeral, but does not know "what the details are yet".
He added that he has not spoken to King Charles III since his mother's passing, saying: "I know him, I haven't spoken to him, I did not call him yet."
Mr Biden was the 13th and final American president to meet the Queen, whose reign spanned seven decades.
The Queen had met every American president since Dwight Eisenhower, except for Lyndon Johnson because he did not visit Britain during his presidency.
In a statement, Mr Biden and First Lady Jill Biden said the Queen's "legacy will loom large in the pages of British history, and in the story of our world".
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While the president has committed his attendance to the monarch's funeral, other world leaders have not been as forthcoming.
It does not look like Russia's President Vladimir Putin will be appearing at the ceremony, with a top Kremlin spokesperson saying the Queen has not "held a place in the hearts of Russians".
Following the news of her passing, Mr Putin sent King Charles a telegram offering his condolences and wishing him "courage and perseverance" in the face of his "irreparable loss".
However, on Friday, spokesman Dmitry Peskov said: "I don't think she (Queen Elizabeth II) has held a place in the hearts of Russians.
"She was treated with respect in Russia, as elsewhere in the world, she was treated with respect for her wisdom, for her international authority. Such qualities are in short supply on the international stage."
He added that it has not been announced whether a Russian representative would be required to participate in any events for the Queen, with UK-Russia relations at a low ebb due to the war in Ukraine.
"All this should be announced by the Royal Court or British authorities," Mr Peskov said.
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In Turkey, President Recep Tayyip Erdogan said he would like to attend Her Majesty's funeral, providing his schedule permits it.
He told reporters that he knew the Queen, having met her at Buckingham Palace twice, and he has sent his deepest condolences to the royal family.
"If we find the opportunity, we would like to be present at this ceremony," Mr Erdogan said.
One person who is expected to attend the Queen's funeral is Emmanuel Macron.
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The French president expressed "deep sadness" and a sense of "emptiness" after the passing of the monarch, and praised her "great affection for France."
In a video message, Mr Macron said the Queen mastered "our language, loved our culture and touched our hearts".
Describing her as a "great head of state", he added that Britain and France had forged a "warm, sincere and loyal partnership" under her reign.
Speaking in English, Mr Macron said: "To you, she was your Queen. To us, she was The Queen."
Japan's Emperor Naruhito is planning to attend the funeral and he might be accompanied by Prime Minister Fumio Kishida, Japanese media have reported.
It would be the emperor's first overseas trip since acceding to the throne in May 2019.
Empress Masako has also expressed a wish to attend and the Japanese government is arranging their trip, NTV, TBS and other media said on Friday, citing government sources.