NICOLA Sturgeon was among the political leaders who paid tribute today to Martin McGuinness, the former IRA commander turned peacemaker, whose death was announced this morning.

In a statement the First Minister said McGuinness will be remembered for his commitment, alongside that of the late DUP leader Ian Paisley, for bringing peace and reconciliation to Northern Ireland.

She said that "without his hard and brave work to bridge the divide, peace would not have been achieved".

She added: "I had the opportunity in recent years to get to know Martin through our work in the British Irish Council and Joint Ministerial Committee - his deep understanding of both the importance and fragility of the peace process, and also his optimism for the future, was obvious to all.

"While he had been unwell for a few months, his untimely death will still come as a shock to many and my thoughts and sympathies are with his wife, wider family and friends."

McGuinness was 66 and had been suffering from a rare heart condition.

Born in Derry in the 1950 he was working as a butcher's assistant when the Troubles erupted in the late 1960s. Angry about the rough handling of protesters demanding civil rights for Catholics, McGuinness was quickly drawn into the ranks of the IRA.

By January 1972, when soldiers from the Parachute Regiment killed 14 people in his hometown on what became known as Bloody Sunday, McGuinness was second in command of the IRA in the city.

The Saville Inquiry into the deaths concluded he had probably been armed with a sub-machine-gun on the day, but had not done anything that would have justified the soldiers opening fire.

He rose to become a senior IRA commander but by the early 1990s began to realise paramilitary action would not bring about a United Ireland.

His shift in attitude helped established peace talks ultimately leading to the 1998 Good Friday Agreement and the setting up of the power sharing Assembly at Stormont, where, as Sinn Fein leader in the Assembly, he eventually became deputy First Minister. At Stormont he forged an unlikely alliance with Ian Paisley, the fiercest - and loudest - critic of the republican movement, where the two old foes became known as “the Chuckle Brothers”.

McGuinness stood down from his post in January in protest against the DUP's handling of an green energy scandal, in a move that triggered a snap election.

Alex Salmond also paid tribute today.

The former First Minister, now the SNP's foreign affairs spokesman, tweeted his "sympathy and condolences" to McGuinness' family, along with a statement that recalled his visit to Northern Ireland at the launch of the Stormont powersharing agreement.

"As first minister of Scotland, I was asked by Ian Paisley and Martin McGuinness to go to Northern Ireland in 2007 to support their new power sharing administration by addressing the Northern Irish Assembly," he said.

"I gladly did so and found a remarkable partnership, which was the anchor of the institutions consolidating the peace process.

"The friendship which developed between them was real, enduring and profound, private as well as public and allowed Northern Ireland to move away from violence. They were both solid friends of Scotland.

"That political journey was accompanied by Martin McGuinness' own personal journey. It is why it is right to both mourn his passing and recognise his contribution today. My sympathy and condolences go to Martin's family."

Long-time Sinn Fein colleague Gerry Adams described him as a "passionate republican who worked tirelessly for peace and reconciliation and for the reunification of his country".

Adams posted Irish folk singer Luke Kelly's Song for Ireland along with the tweet "A song for Martin McGuinness. I measc Laochra na n-Gael go raibh a anam dilis", which translates as "Among heroes of Gael he had a faithful soul".

In a statement, President of Ireland Michael D Higgins paid tribute to the ex-IRA commander's "immense contribution to the advancement of peace and reconciliation in Northern Ireland".

He said: "The world of politics and the people across this island will miss the leadership he gave, shown most clearly during the difficult times of the peace process, and his commitment to the values of genuine democracy that he demonstrated in the development of the institutions in Northern Ireland.

"As President of Ireland, I wish to pay tribute to his immense contribution to the advancement of peace and reconciliation in Northern Ireland - a contribution which has rightly been recognised across all shades of opinion."

He added: "In addition to his services in public life, as an inclusive believer in community in all its forms he will also be remembered for his warm support for Derry GAA and Derry FC.

"His death leaves a gap that will be difficult to fill. May he rest in peace."

Donald Tusk, President of the European Council, said: "Sad to learn of sudden passing of Martin McGuinness. His contribution to peace in Northern Ireland will endure."

Prime Minister Theresa May said although she could never "condone the path he took in the earlier part of his life, Martin McGuinness ultimately played a defining role in leading the republican movement away from violence".

She added: "In doing so, he made an essential and historic contribution to the extraordinary journey of Northern Ireland from conflict to peace."

Former Northern Ireland secretary Lord Hain said McGuinness was "absolutely crucial" to the peace process.

"He had the grassroots credibility of a republican leader and former IRA commander, that could enable him, along with Gerry Adams, to take his followers, to take republicans, from the past of terror and horror into a democratic future, which is what he did," Lord Hain told the BBC Radio 4 Today programme.

"Sometimes in the history of conflicts - and, goodness me, the island of Ireland has been involved in centuries of conflict with Britain - you need leaders who can rise above their past and, at that point, Martin McGuinness certainly stood the test and proved to be an indispensable figure."

The Labour former cabinet minister revealed that McGuinness also had an unlikely love of the England cricket team.

"I discovered he was a fan of the England cricket team - this was a hardline republican - but I realised watching the Ashes series on the television in the corner of my office in Stormont Castle that he actually was following the England cricket team, he knew all the players," Lord Hain said.

Irish Taoiseach Enda Kenny said: "I was deeply saddened to hear of the death of Martin McGuinness today. His passing represents a significant loss, not only to politics in Northern Ireland but to the wider political landscape on this island and beyond.

"Martin will always be remembered for the remarkable political journey that he undertook in his lifetime. Not only did Martin come to believe that peace must prevail, he committed himself to working tirelessly to that end.

"Martin was one of the chief architects of the Good Friday Agreement and he worked resolutely in the years that followed it in pursuit of its full implementation. I got to know Martin well in recent years, including through our working together in the North South Ministerial Council. His commitment to securing enduring peace and prosperity for all of the people of Northern Ireland was unwavering throughout this time. He strove to make Northern Ireland a better place for everyone, regardless of background or tradition.

"Above all, today is an especially sad day for Martin's family - his wife Bernie, and his children - and for the people of Derry, who held a special place in Martin's heart.

"My deepest sympathies are with all of them at this sad and difficult time."

Labour leader Jeremy Corbyn said on Twitter: "Martin McGuinness played a huge role in bringing about peace in Northern Ireland. He was a great family man and my thoughts are with them."

In Northern Ireland, Jim Allister, leader of the Traditional Unionist Voice said McGuinness had taken secrets about his IRA past to the grave.

"Naturally, the passing of anyone causes grief and sorrow to their family and friends. All such families deserve condolences," he said.

"In the case of Martin McGuinness, he lived many more decades than most of his victims."

He added: "So today my primary thoughts are with the many victims of the IRA who never reached the age of 66; of men and women who never got to see their grandchildren because their lives were cut short by murderous republicanism; of children stolen from their parents and grandparents by the organisation in which McGuinness was a commander."