By Philip Pullella
VATICAN CITY (Reuters) - Pope Francis will host the divided leaders of South Sudan at the Vatican next week to help them solidify a faltering peace agreement ending the civil war in the world's youngest country.
The meeting, which a Vatican statement on Wednesday called a "spiritual retreat", could increase the chances of a visit by the pope to the South Sudanese capital, Juba.
The leaders will include President Salva Kiir, First Vice President and former rebel leader Riek Machar and the other four vice presidents and Cardinal Pietro Parolin, the Vatican's Secretary of State, told reporters.
"We know the pope wants to go there and we know that the situation has improved a little, especially after the agreement was signed, and also because of the good will of the people who are involved the situation," Parolin said.
Oil-producing South Sudan, which became independent in 2011, descended into civil war in December 2013 when a dispute between Kiir and Machar -- who was vice president then -- sparked fighting, often along ethnic lines.
In September the two sides signed a power-sharing deal calling on the main rival factions to assemble, screen and train their respective forces and unify them into a national army before the formation of a unity government next month.
That has not happened. The government, which has faced frequent international criticism over corruption and rights abuses, blames a lack of funding from donors.
"It will be a moment of spirituality and above all, it will help make them aware of the responsibility that politicians and authorities have," Parolin said on the sidelines of a conference on religious freedom at the U.S. embassy to the Vatican.
All six of the leaders are Christian, as is more than half the population of South Sudan. Sudan is predominantly Muslim.
About 400,000 people have been killed and more than a third of the country's 12 million people uprooted by the civil war - a conflict punctuated by multiple rounds of mediation followed by renewed bloodshed.
The conflict sparked Africa's worst refugee crisis since the 1994 Rwandan genocide and plunged parts of the country into famine. More than 875,000 refugees have fled into neighbouring Uganda since the war broke out.
Parolin said the pope, who met Kiir at the Vatican on March 16, would attend at least part of the retreat. Last month, the Vatican said the pope had asked aides to resume planning for a visit that was scrapped in 2017 because of security concerns.
A Church source said the retreat would be held on April 10-11.
(Additional reporting by Katharine Houreld in Nairobi)