Jean Kennedy Smith, a US envoy who played a key role in Northern Ireland peace process, has died aged 92.

Her daughter Kym confirmed her death to US media on Thursday.

Ms Smith was the second youngest of the nine Kennedy siblings, who included President John F Kennedy and Senator Robert F Kennedy.

A diplomat, activist and humanitarian, Ms Smith was the last-surviving child of Joseph P Kennedy and Rose Fitzgerald.

Ms Smith served as the US ambassador to Ireland in the 1990s, playing an important role in attempts to end sectarian violence in Northern Ireland.

On Thursday, Mick Mulvaney, US special envoy to Northern Ireland, said: "Ambassador Smith played a critical role in advancing peace in Northern Ireland, leveraging deep personal empathy and courage.

"We join with colleagues and friends to offer condolences to her family on her passing."

In 2011, US President Barack Obama awarded Ms Smith the Presidential Medal of Freedom, the highest civilian honour in the country.

She led a quiet life until she entered politics, doing philanthropy work and keeping out of the limelight her prestigious family name attracted.

Her first taste of politics came in 1960, when she campaigned across the country in support of her brother, John F Kennedy, who was running for the presidency.

Controversial step helped lead to peace

By Mark Devenport, BBC Northern Ireland political editor

Jean Kennedy Smith was appointed as the US Ambassador to Dublin in 1993 - a particularly sensitive time in Northern Ireland with the IRA considering whether to call an end to its violent campaign of more than two decades.

The new ambassador brought the celebrity of her famous Irish American family to the role. She soon became convinced that granting a short term US visa for the Sinn Féin leader Gerry Adams - against the wishes of the UK government - could play an important role in demonstrating to Irish republicans that adopting a peaceful political strategy would pay dividends.

Ambassador Kennedy Smith did not have to convince President Bill Clinton of the reasons for granting a visa - he had already promised much the same when campaigning for the White House. But she did clash with other US officials, including two diplomats at her own embassy who voiced their opposition. The dispute became so bitter it earned her an official reprimand from the US Secretary of State Warren Christopher.

In the event Gerry Adams made a highly publicised 48-hour visit to New York in February 1994 - a move which paved the way for the IRA to call a ceasefire six months later.

When Bill Clinton appointed Jean Kennedy Smith as ambassador he called her "as Irish as an American can be". When she finished her term as US ambassador in 1998, she received Irish citizenship for "distinguished service to the nation".

Ms Smith's role in bringing the Irish Republican Army (IRA) to the negotiating table was seen as an important step in ending decades of sectarian violence in Northern Ireland.

"The Irish people were willing to take me at face value, to give me the benefit of the doubt because I was a Kennedy," Ms Smith said of her time in office in 1998. "I was a cog, really, in the machine that was moving. I was fortunate to be here to perhaps add momentum to what was happening."

Born on 20 February, 1928 in Boston, Massachusetts, Ms Smith studied English at Manhattanville College.

In 1945, she was asked to launch the USS Joseph P Kennedy Jr, a newly commissioned Navy destroyer named for her brother, who died during World War Two.

She published a memoir in 2016 called The Nine of Us in which she remarked that her childhood seemed "unexceptional".

"It is hard for me to fully comprehend that I was growing up with brothers who eventually occupy the highest offices of our nation, including president of the United States," she explained.

In 1956, Jean Kennedy married Stephen E Smith, an executive in a transportation company founded by his grandfather.

Mr Smith, a New York financier who advised the Kennedy family and oversaw their fortune, died in 1990.

The couple are survived by their two daughters, Kym and Amanda, two sons, Stephen Jr and William, and six grandchildren.