Speaking earlier this evening, Mr Smith said:
Seamus Mallon was passionate about politics and political debate.
His leadership, with David Trimble, of the first Northern Ireland Executive formed after the Belfast/Good Friday Agreement in 1999 was marked by a generosity of spirit - he sought to represent the views of communities across Northern Ireland.
Seamus Mallon championed the development of policing in Northern Ireland, fighting for the necessary reform to ensure the full participation of nationalists in the new policing structures introduced following the Good Friday Agreement.
I want to also express my sincere condolences to his family, friends and to the SDLP.