Some 250,000 mourners paid their respects to Pope Francis over a three-day lying-in-state, the Vatican said on the eve of his funeral.

World leaders and dignitaries were arriving in Rome on Friday, to attend what will be a huge gathering in St Peter's Square for his requiem mass.

The final mourners had a chance to see the Pope close up in the grand surrounds of St Peter's Basilica, before his coffin was closed in private.

US President Donald Trump and UK Prime Minister Sir Keir Starmer were among those due to arrive into Rome on Friday, and the Prince of Wales is also set to attend the mass on behalf of his father the King.

Irish President Michael D Higgins was among those to pay his respects in the basilica, having arrived earlier in the day.

The leader of Catholics in England and Wales, Cardinal Vincent Nichols, has predicted the funeral will be a "masterpiece" in stage-managing "big egos".

A Vatican spokesperson has confirmed Francis's birth country of Argentina, then Italy, will take precedence.

Thereafter, reigning sovereigns will be seated "in alphabetical order, but in French language", followed by heads of state.

Ireland's delegation comes ahead of both Prince William and the British Government delegation in the official order of precedence, because it is led by head of state Mr Higgins.

It falls between groups from Indonesia and Iceland, also led by those countries' heads of state.

Haakon, the Crown Prince of Norway, and William follow soon after in a category set aside for crown princes.

The British Government delegation includes Sir Keir Starmer and his wife Victoria, as well as Foreign Secretary David Lammy.

US President Donald Trump and his wife First Lady Melania are seated ahead of both the Irish and British delegations, in between Estonia and Finland.

Cardinal Nichols, who will take part in his first conclave to elect a new pope in the coming weeks, said the funeral organisers are well used to dealing with the sensitivities of such big events.

He said the funeral will be "without a doubt another masterpiece of stage management when you consider those state leaders who have high opinions of their importance".

He added: "In the past, I've seen it here over and over again that the combination of Rome and the Holy See, they actually are geniuses at dealing with these big events.

"I think they've been doing it since the emperors ruled Rome - that they know how to deal with big egos.

"And I think every leader of a nation that comes here on Saturday will go home reasonably content."

Scaffolding has been erected to provide international media with the best vantage points overlooking St Peter's Square while there is a strong Italian police presence managing numbers and security.

Following Saturday's open-air funeral in the square, Francis's remains will be taken through the streets of Rome in another break with tradition, as his body is brought to a simple underground tomb in the basilica of Saint Mary Major, as per his instructions.

The Vatican said a group of "poor and needy" people will be present on the steps leading to the basilica to pay their last respects before the interment of the coffin, in a nod to Francis's particular care for the downtrodden.