In a message for World Day of Peace 2013, Pope Benedict XVI has described same-sex marriage as a threat to justice and peace, adding that it will spark harm for society.

The Catholic leader said on Friday: “There is also a need to acknowledge and promote the natural structure of marriage as the union of a man and a woman in the face of attempts to make it juridically equivalent to radically different types of union.

“Such attempts actually harm and help to destabilise marriage, obscuring its specific nature and its indispensable role in society”, the Pope told worshipers.

ANSA reports the comments led to a wave of criticism from gay rights groups and some centre-left Italian politicians.

Flavio Romani, the head of the Arcigay association, said that the Pope’s message “arms the homophobes of all countries with an invitation to take part in a crusade against marriage between people of the same sex”.

Nichi Vendola, the gay governor of Puglia and the leader of the left-wing SEL party, was equally dismayed.

“I’d like to ask the Catholic Church why it is trying to run away from dialogue, from listening, from debate,” he said.

In January, the Pope warned that introducing equal marriage would risk the future of humanity itself.

Meanwhile, on Thursday, he was pictured giving a blessing to Rebecca Kadaga, the Speaker of the Ugandan Parliament, who has promised to pass the country’s notorious Anti-Homosexuality Bill as a “Christmas gift”.