Former US first lady Barbara Bush has died at the age of 92.

Her death was announced in a statement from the office of George HW Bush, the former president and Ms Bush's husband of 73 years. A funeral date is yet to be announced.

Earlier this week Ms Bush decided to forego additional medical treatment after a series of hospital visits.

A spokesman did not elaborate on the nature of her health problems, but she had long received treatment for a thyroid condition known as Graves' disease.

Born in New York, Ms Bush met George HW Bush at a school dance as a teenager.

They raised their family in Texas, where the Bush family became a formidable political dynasty.

Barbara Bush shuts down people shaming her for being the First Lady

“Barbara Bush was a fabulous First Lady and a woman unlike any other who brought levity, love, and literacy to millions,” former president George W Bush said in a statement. “To us, she was so much more. Mom kept us on our toes and kept us laughing until then”.

Tributes poured in from across the political spectrum.

Donald Trump and his wife Melania released a statement lauding her efforts to promote literacy and her role as “an advocate of the American family”.

Barbara Bush: life in pictures Show all 10 1 /10 Barbara Bush: life in pictures Barbara Bush: life in pictures An infant George W. Bush with his mother Barbara Bush and his father George Bush posing for a portrait in New Haven, CT, April 1947. Barbara Bush: life in pictures George W. Bush (C) poses with father George Bush and his mother Barbara Bush in Rye, New York, summer 1955. Getty Images Barbara Bush: life in pictures George Bush, candidate for the Republican nomination for the U.S. Senate, gets returns by phone at his headquarters in Houston as his wife Barbara, beams her pleasure at the news, in June, 1964. AP Barbara Bush: life in pictures George Herbert Walker Bush poses with his wife Barbara during his campaign for Congress in the 1960's. AFP/Getty Images Barbara Bush: life in pictures George Herbert Walker Bush poses with his wife Barbara in Beijing in 1974. AFP/Getty Images Barbara Bush: life in pictures First Lady Barbara Bush talking to her dog Millie as she and granddaughter Barbara Bush, age nine, wait for US President George Bush to return to the White House. September 1991, in Washington,DC. AFP/Getty Images Barbara Bush: life in pictures US First Lady Barbara Bush (L) as she prepares to throw a rugby ball. February 1992,in Washington,DC. AFP/Getty Images Barbara Bush: life in pictures First Lady Barbara Bush and her son George Bush Jr attend the 1992 Republican National Convention on August 17, 1992 in Houston. AFP/Getty Images Barbara Bush: life in pictures U.S. President George Bush and First Lady Barbara Bush work their way through a crowd gathered to welcome them in August 1992, in the Astroarena. AFP/Getty Images Barbara Bush: life in pictures First Lady Barbara Bush greets the delegates attending the Republican Convention before beginning her speech. August 1992, in Houston, Texas. AFP/Getty

“She will long be remembered for her strong devotion to country and family, both of which she served well”, the statement said.

Barack and Michelle Obama hailed Ms Bush “for the way she lived her life - as a testament to the fact that public service is an important and noble calling; as an example of the humanity and decency that reflects the very best of the American spirit”.

The statement announcing Ms Bush's death noted she was a “relentless proponent of family literacy”, a cause that led her to launch the Barbara Bush Foundation for Family Literacy, which seeks to boost reading and writing skills.

First Lady Barbara Bush and her son George Bush Jr attend the 1992 Republican National Convention (AFP/Getty) (AFP/Getty Images)

“I chose literacy because I honestly believe that if more people could read, write and comprehend, we would be that much closer to solving so many of the problems that plague our nation and our society,” Ms Bush told a Wellesley College audience in 1990.

She also held the distinction of seeing both both her husband and her son become president of the United States.

After her husband George HW Bush governed from 1989 to 1993, Ms Bush's son George W Bush was elected to two terms in 2000 and in 2004.

Her son Jeb Bush served as governor of Florida and was the favoured presidential candidate for much of the Republican establishment at the outset of the 2016 presidential campaign.

In pictures: President Bush’s immediate response to 9/11 Show all 12 1 /12 In pictures: President Bush’s immediate response to 9/11 In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush was visiting Emma E Brooker Elementary School in Sarasota, Florida as news of the attack on the World Trade Center broke In pictures: President Bush’s immediate response to 9/11 11 September 2001 The president and his staff, including Press Secretary Ari Fleischer (L) were then brought to a holding room at the school, where he prepared to address the nation In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush was then rushed onto Air Force One and was flown to Barksdale Air Force Base in Louisiana. He watched television coverage of the attacks from his office on the plane In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush talks on the telephone at the General Dougherty Conference Center at Barksdale Air Force Base In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush is seen with his senior adviser Karl Rove at Barksdale Air Force Base In pictures: President Bush’s immediate response to 9/11 11 September 2001 The president with White House Chief of Staff Andrew Card at Barksdale Air Force Base. Before leaving the base, the president held a press conference at which he said, “Make no mistake: The United States will hunt down and punish those responsible for these cowardly acts” In pictures: President Bush’s immediate response to 9/11 11 September 2001 The president was consoled by Lt Col Cindy Wright of the White House Military Office aboard Air Force One. After leaving Louisiana, the president was flown to Offutt Air Force Base in Nebraska before he headed back to Washington In pictures: President Bush’s immediate response to 9/11 11 September 2001 President Bush arrived at the White House Presidential Emergency Operations Center around 7 pm. Here he is shown with his wife, First Lady Laura Bush, Vice President Cheney and National Security Adviser Condoleezza Rice In pictures: President Bush’s immediate response to 9/11 11 September 2001 At 8:30 pm, the president addressed the nation from the White House. In his speech, he set the tone for the wars to come in Afghanistan and Iraq In pictures: President Bush’s immediate response to 9/11 11 September 2001 “I’ve directed the full resources for our intelligence and law enforcement communities to find those responsible and bring them to justice,” the president said. “We will make no distinction between the terrorists who committed these acts and those who harbour them” In pictures: President Bush’s immediate response to 9/11 11 September 2001 The president’s speech on the teleprompter In pictures: President Bush’s immediate response to 9/11 11 September 2001 Immediately following the speech, the president had a national security meeting with Secretary of Defense Donald Rumsfeld, Vice President Dick Cheney, National Security Adviser Condoleezza Rice, White House Chief of Staff Andrew Card and others

In a characteristic display of her reputation for blunt talk, Ms Bush initially cast doubt on another of her sons seeking the presidency.

“We've had enough Bushes,” Ms Bush said, though she called Jeb Bush “by far the most qualified” and later supported his candidacy.

She made no secret of her dislike for Mr Trump, who savaged Jeb Bush on the way to winning the nomination, saying in February of 2016 that she was “sick of him”.

“He's said terrible things about women, terrible things about the military,” she said. “I don't understand why people are for him, for that reason.”