Bill Clinton has told mourners at Martin McGuinness’ funeral that the people of Northern Ireland must finish the work he started.

The former US president was speaking following Mass for the former IRA commander who, a priest said, “became a mainstay of the peace process”.

Mourners included Democratic Unionist Party leader Arlene Foster, who received a round of applause.

The ex-paramilitary turned Sinn Féin politician died on Tuesday aged 66.

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• From terror to peacemaker
• Obituary: Martin McGuinness
• Analysis: McGuinness’ IRA past
• Colleagues divided on legacy

President Clinton told mourners: “I came to treasure every encounter with Martin McGuinness. If you want to continue his legacy go and finish the work he has started.”

Fr Michael Canny, who was a personal friend of Mr McGuinness, said there were people in the church “whose presence would have been unthinkable only a generation ago”.

“The presence of those political rivals and opponents who have come to pay their respects is the most eloquent testimony to the memory of Martin McGuinness,” he said.

Mr McGuinness was a “man of simple tastes who ascended to the political summit”, he continued.

“He visited the White House, Downing Street and Windsor Castle, but only ever felt at home in his beloved Bogside, returning to his wife and family at every opportunity.”

He said Mr McGuinness was a “complex man, born into a community where faith, Catholicism and nationalism were intertwined” and his life was a “remarkable journey”.

“He was the Sinn Féin leader who first shared power, then became friends with the late Dr Ian Paisley; he was the IRA commander who became a mainstay of the peace process,” he added.

Mr McGuinness’ grandchildren read prayers and there were words from Rev Harold Good, a former Methodist Church president, and the Rev David Latimer, from First Derry Presbyterian Church.

A message was read out on behalf of Archbishop Eamon Martin, leader of the Catholic Church in Ireland, who could not attend the funeral but had visited the McGuinness family on Wednesday.

The service was relayed to the large crowds outside the church.

Mr McGuinness’ coffin is draped in an Irish tricolour but there will be no paramilitary trappings for the one-time IRA commander.

Taoiseach (Irish Prime Minister) Enda Kenny, Irish President Michael D Higgins, Secretary of State James Brokenshire and former Scottish first minister Alex Salmond are among the high-profile political figures attending.

At the scene

By Ciaran McCauley

On Tuesday afternoon, the city of Derry came to a standstill for the funeral of Martin McGuinness.

Thousands lined the short route from his home in Westland Street to his parish church, Long Tower.

Onlookers crowded along pavements and stood on balconies as he made his final journey.

They often broke into applause as he passed through the Bogside, an area that saw some of the most infamous events of the Troubles.

Mr McGuinness’ legacy and impact – his shift from IRA commander to pivotal architect of the peace process – will be debated for decades.

Regardless, this is the closest the city of Derry has ever come to hosting a state funeral.

Numerous politicians from Northern Ireland’s Assembly were also there, as was police chief George Hamilton.

There had been reports that former British prime minister Tony Blair, who worked with Mr McGuinness to secure the Good Friday Agreement peace deal, would attend but his spokeswoman confirmed he was not there.

Following Requiem Mass, Mr McGuinness is being buried in the republican plot in the city cemetery where Sinn Féin leader Gerry Adams will deliver a graveside oration.

Folk singer Christy Moore will sing the final song at the graveside.

The Irish tricolour is flying at half mast at the official residence of the Irish president as well as the Dáil (Irish parliament) as a mark of respect to Mr McGuinness.

Writing in the Belfast Telegraph, Mrs Foster said she recognised some will be critical of her decision to attend the funeral of a former IRA leader but added she wanted to pay “respect to his family”.

Mr McGuinness had been suffering from a rare heart condition, and he died at the Altnagelvin hospital, with his family by his bedside.

Many tributes from across the political spectrum have been paid to the republican figurehead.

However, some victims of the Troubles have expressed revulsion at media coverage of his death, with critics saying that Mr McGuinness was lauded as a peacemaker despite never having apologised for his IRA past.