Senior IRA commander Brian Keenan died early today after a battle with cancer.
The west Belfast-based republican was a key figure in the organisation during the peace process.
A Sinn Féin spokesman confirmed his death.
Mr Keenan was born in Swatragh in Co Derry in 1942 and grew up in west Belfast.
He was a member of the IRA's army council and masterminded the IRA bombing campaign in England, which culminated in the Balcombe Street siege in London.
He served a lengthy prison sentence in Northern Ireland and was also jailed in the Republic for a time.
Mr Keenan was considered to be a hard line republican, but his support for Gerry Adams and Martin McGuinness during the peace process persuaded many IRA members to back the process and was crucial to its success.
Sinn Féin President Gerry Adams expressed his deep sense of
personal loss and regret at the death of Brian Keenan.
He said Mr Keenan was was a 'formidable republican leader over 40 years of activism.
He added that Mr Keenan's strong endorsement of the Sinn Féin peace strategy was crucial in securing the support of the IRA leadership for the series of historic initiatives that sustained the peace process through its most difficult times.
Mr Adams said that Mr Keenan's dedication to the republican struggle was unswerving.
He said that Mr Keenan will be greatly missed by the many
republicans who over the years have been touched by his generosity, friendship, and humour.