Pope Francis has ended his peace pilgrimage to South Sudan by celebrating an open air mass attended by tens of thousands in Juba.

He urged the congregation to reject what he called the "venom of hatred", and told them to lose no opportunity to build peace.

And he pleaded with the country's leaders to focus on ending conflict.

Before leaving, he told the crowd: "Dear brothers and sisters, I return to Rome with you even closer to my heart."

Excited Catholics, some who camped overnight for the Mass, told Reuters it was a joyful moment.

"To this moment I do not sleep, I was very excited," Jovana Buyom said.

"We are really very happy with the coming of Pope because he will give us the message of peace, we can unite as South Sudanese people," Juaj Bol Ayuel said.

The Mass, which took place at the John Garang Mausoleum in front of an audience of 70,000 according to estimates, was filled with cheerful worshippers waiving flags and deep in prayer.

The religious ceremony fell on the last day of the Pope's visit to South Sudan, which was his first to the country.

Since it got independence in 2011, the country has been wracked by civil war after the president fell out with his then vice president in 2013.

Despite a peace deal in 2018, violence driven by ethnic tensions has continued - more than 400,000 people are thought to have died as a result of the conflict.

At least 20 people were killed in a cattle raid on the eve of the religious leaders' visit.

The Pope, who visited the country alongside other Christian leaders - the Archbishop of Canterbury, Justin Welby, and the Moderator of the General Assembly of the Church of Scotland, Rev Iain Greenshields - has been on a peace mission and pleaded with South Sudanese clergy to raise their voices against injustice on Saturday.

He also told them that they cannot remain neutral against injustice: "If we want to be pastors who intercede, we cannot remain neutral before the pain caused by acts of injustice and violence. To violate the fundamental rights of any woman or man is an offence against Christ."

The Pope had a similar message of peace and reconciliation when he visited the Democratic Republic of Congo earlier this week.