Pope Leo has criticised the treatment of prisoners in Equatorial Guinea, ahead of a visit to a jail known for its dire conditions.

He addressed the Central African nation on Wednesday at a Mass that drew some 100,000 people, including Teodoro Obiang Nguema Mbasogo, the country's leader and the world's longest-serving president.

Pope Leo said: My thoughts go to the poorest, to families experiencing difficulty and to prisoners who are often forced to live in troubling hygienic and sanitary conditions.

Oil-rich Equatorial Guinea, a country with a poor human rights record and vast income inequalities, is the Pope's final stop on a four-nation tour of Africa.

In the evening on Wednesday, his last full day of the tour, Pope Leo is scheduled to visit an infamous prison in the economic capital, Bata.

Amnesty International has stated that inmates in Bata prison are reportedly routinely beaten as punishment. Numerous prisoners have neither been seen nor heard from, and their relatives do not know whether they are alive or dead, the human rights organization noted.

During his Mass at the Basilica of the Immaculate Conception in the town of Mongomo, Pope Leo urged Equatoguineans to serve the common good rather than private interests, bridging the gap between the privileged and the disadvantaged.

He also called for the country's resources to be used to improve the lives of the wider population, not just a privileged few, warning that the future of the country depended on the people's choices.

Obiang's government has faced accusations of corruption, diverting the country’s oil revenues for the benefit of the elite. Transparency International has listed Equatorial Guinea among the world's most corrupt states, while the World Bank reports that over half of Equatoguineans live in poverty.

Political opposition in Equatorial Guinea is barely tolerated, and the lack of a free press severely hampers reform efforts, with all broadcast media controlled by the government or its allies.

“May there be greater room for freedom and may the dignity of the human person always be safeguarded,” the Pope stated emphatically.

During his tour of Africa—visiting Algeria, Cameroon, and Angola—Pope Leo has addressed issues of tyranny and exploitation of the continent, criticizing leaders for neglecting their citizens in favor of personal gains.