Tributes poured in Monday from across the political spectrum following the death of John Hume, who won the Nobel Peace Prize for his role in ending decades of deadly sectarian violence in Northern Ireland.

The former leader of the mainly Catholic Social Democratic and Labour Party (SDLP) helped forge the 1998 Good Friday peace agreement in the British province after a conflict that left 3,500 people dead.

The 83-year-old Hume, who had suffered with dementia in his later years, died on Monday after a short illness, his family said.

A consistently moderate voice during the so-called Troubles, he shared the Nobel in 1998 with David Trimble of the Ulster Unionist Party for their cross-community efforts that culminated in the landmark peace deal between Belfast, Dublin and London.

John Hume, a former Northern Ireland politician, won the Nobel Peace Prize in 1998
John Hume, a former Northern Ireland politician, won the Nobel Peace Prize in 1998 AFP / PETER MUHLY

The agreement shepherded in a new era for Northern Ireland after three decades of bloody strife between the largely Catholic nationalist community, who want to reunify with Ireland, and Protestant unionists who want to remain part of the United Kingdom.

British Prime Minister Boris Johnson hailed a "political giant", while Irish Prime Minister Micheal Martin said: "He was one of the towering figures of Irish public life of the last century.

"His vision and tenacity saved this country."

John Hume helped lead the cross-community peace process that culminated in the landmark Good Friday agreement
John Hume helped lead the cross-community peace process that culminated in the landmark Good Friday agreement AFP / GERRY PENNY

Hume had been largely out of the public spotlight since resigning as leader of the SDLP in 2001, citing ill health. He had been in a nursing home in the Northern Irish city of Londonderry, where he was born.

"John was a husband, a father, a grandfather, a great-grandfather and a brother. He was very much loved, and his loss will be deeply felt by all his extended family," a family statement said.

The SDLP, which he helped to found in 1970, said: "We all live in the Ireland he imagined -- at peace and free to decide our own destiny."

Northern Ireland's First Minister Arlene Foster, leader of the pro-British Democratic Unionist Party, called Hume "a giant in Irish nationalism".

"In our darkest days he recognised that violence was the wrong path (and) worked steadfastly to promote democratic politics," she added.

British Prime Minister Tony Blair (C) talks to the press after a meeting with Ulster Unionist leader David Trimble (L) and SDLP leader John Hume (R)
British Prime Minister Tony Blair (C) talks to the press after a meeting with Ulster Unionist leader David Trimble (L) and SDLP leader John Hume (R) AFP / GERRY PENNY

Former US President Bill Clinton, one of the architects of the 1998 accord, said he and wife Hillary were "deeply saddened by the passing of our friend John Hume".

"With his enduring sense of honour, he kept marching on against all odds towards a brighter future for all the children of Northern Ireland," he said in a statement.

Ex-British prime minister Tony Blair, another to help craft the deal, praised Hume as "a visionary who refused to believe the future had to be the same as the past".

"His contribution to peace in Northern Ireland was epic and he will rightly be remembered for it," he added.

Born in the republican stronghold of Londonderry in 1937, Hume joined the province's civil rights movement in the late 1960s as Catholics demanded equality in housing, voting and other issues.

He was elected to Northern Ireland's parliament as an independent lawmaker, becoming a founding member of the SDLP in 1970, before later serving as a member of the European Parliament and then Britain's House of Commons.

European Union chief Ursula von der Leyen said with Hume's death Europe had "lost a great champion of peace".

With several ceasefires by the Irish Republic Army (IRA) paramilitary group in the 1990s, he had worked to engage US politicians, notably Clinton, in the peace process.

Gerry Adams, the leader of the republican Sinn Fein party -- the political wing of the IRA -- called Hume's willingness to meet with him in 1986 the "breakthrough moment in Irish politics".

"When others talked endlessly about peace John grasped the challenge and helped make peace happen," he said.

In his 1998 Nobel acceptance speech Hume said understanding differences -- whether racial, religious or national -- was key to conflict resolution.

"The answer to difference is to respect it," he added.

Hume's family said his funeral would be arranged in accordance with current government regulations severely limiting the number of attendees due to the risk of coronavirus.