Northern Ireland's former deputy first minister and ex-IRA commander Martin McGuinness has died aged 66.
Sinn Fein said in a statement : "It is with deep regret and sadness that we have learnt of the death of our friend and comrade Martin McGuinness who passed away in Derry during the night. He will be sorely missed by all who knew him."
Mr McGuinness stood down in January in protest at the DUP's handling of the 'cash for ash' energy scandal, triggering a snap election.
His retirement came amid health concerns, but he, his family and colleagues did not specify the nature of his illness.
Sinn Fein president Gerry Adams paid tribute to his lifelong friend, saying: "Throughout his life Martin showed great determination, dignity and humility and it was no different during his short illness.
"He was a passionate republican who worked tirelessly for peace and reconciliation and for the reunification of his country.
"But above all he loved his family and the people of Derry and he was immensely proud of both.
"On behalf of republicans everywhere we extend our condolences to Bernie, Fiachra, Emmet, Fionnuala and Grainne, grandchildren and the extended McGuinness family.