* Key political figure during N.Ireland's "Troubles" dies
* Mallon served as Deputy First Minister until 2001
(Adds details, reaction)
By Amanda Ferguson
BELFAST, Jan 24 (Reuters) - Former Northern Ireland Deputy
First Minister Seamus Mallon, one of the architects of the 1998
Good Friday peace agreement, died on Friday aged 83, his Social
Democratic and Labour Party (SDLP) said.
Mallon was one of the key political figures in Northern
Ireland during the three decades of violence between Catholic
nationalists seeking union with Ireland and Protestant unionists
wanting Northern Ireland to remain part of the United Kingdom.
An activist in the civil rights movement of the 1960s that
preceded Northern Ireland's violent "Troubles", during which
3,600 people were killed, Mallon went on to jointly head up the
devolved power-sharing administration that followed the peace
deal.
"Ireland has lost one of its most fierce champions for
justice, equality and peace. Seamus Mallon was a force of
nature," SDLP leader Colum Eastwood said in a statement.
"In the darkest days of conflict, when hope was in short
supply, Seamus represented the fierce thirst for justice that
ran through the SDLP and through communities that had lost so
much to political violence."
Mallon died at his home in the Northern Irish county of
Armagh, a spokesman for the party said.
Mallon served under John Hume as deputy leader of the SDLP
for over two decades when it was the largest Irish nationalist
party in the province, and also alongside Northern Ireland First
Minister David Trimble of the rival Ulster Unionist Party until
2001.
Trimble and Hume were awarded the Nobel Peace Prize for
their efforts in ending the sectarian conflict.
"Very sad to learn of the passing of the great Seamus
Mallon," Irish Foreign Minister Simon Coveney wrote on Twitter.
"He has made an extraordinary contribution to politics and
people on this island. He was tough, intelligent and passionate,
always working for peace and reconciliation."
One of Coveney's predecessors, Micheal Martin, the favourite
to become the next Irish prime minister after a Feb. 8 election,
described Mallon as his "friend and long time political hero."
Britain's Northern Ireland Minister, Julian Smith, said
Mallon dedicated his political career to making Northern Ireland
a better place and together with Trimble, set Northern Ireland
on a new democratic course.
(Reporting by Amanda Ferguson, Writing by Padraic Halpin,
Editing by Catherine Evans and Hugh Lawson)