Leaders from across the world have paid tribute to Queen Elizabeth II following her death on Thursday, praising a monarch who reigned over the United Kingdom for 70 years.

"As the United Kingdom's longest-lived and longest-reigning Head of State, Queen Elizabeth II was widely admired for her grace, dignity, and dedication around the world," said United Nations Secretary-General Antonio Guterres. "She was a reassuring presence throughout decades of sweeping change, including the decolonization of Africa and Asia and the evolution of the Commonwealth."

Calling the queen "a good friend of the UN," Guterres said he would like to pay tribute to her "unwavering, lifelong dedication to serving her people."

In a statement, U.S. President Joe Biden and his wife Jill Biden said Queen Elizabeth's "legacy will loom large in the pages of British history, and in the story of our world."

"In a world of constant change, she was a steadying presence and a source of comfort and pride for generations of Britons, including many who have never known their country without her," they said.

In a message to King Charles III, the son who succeeded the throne, Russian President Vladimir Putin said Queen Elizabeth "rightfully enjoyed the love and respect of her subjects, as well as authority on the world stage."

"I wish you courage and resilience in the face of this difficult, irreparable loss. May I ask you to pass on sincere condolences and support to members of the royal family and the entire people of Great Britain," he said.

Indian Prime Minister Narendra Modi said: "Her Majesty Queen Elizabeth II will be remembered as a stalwart of our times. She provided inspiring leadership to her nation and people. She personified dignity and decency in public life. Pained by her demise. My thoughts are with her family and people of UK in this sad hour."

South African President Cyril Ramaphosa said the queen's "commitment and dedication during her 70 years on the throne remains a noble and virtuous example to the entire world."

Queen Elizabeth was also mourned by Pope Francis, who said he willingly joins "all who mourn her loss in praying for the late Queen's eternal rest, and in paying tribute to her life of unstinting service to the good of the Nation and the Commonwealth."

"Saddened" by the queen's death, European Commission President Ursula von der Leyen said she was "one of the most respected personalities worldwide."

Irish Prime Minister Micheal Martin said Queen Elizabeth's State Visit to Ireland in 2011 "marked a crucial step in the normalization of relations with our nearest neighbor. That visit was a great success, largely because of the many gracious gestures and warm remarks made by the Queen."

French President Emmanuel Macron called Queen Elizabeth "a kind-hearted queen who has left a lasting impression on her country and her century."

The queen "was a beacon of wisdom and principled leadership for seven decades," Jordan's King Abdullah said. "She was a partner for Jordan and a dear family friend. We stand with the people and leadership of the UK at this difficult time."

New UK Prime Minister Liz Truss said the queen "provided us with the stability and the strength that we needed through thick and thin. She was the very spirit of Great Britain - and that spirit will endure."