Catholic leader Pope Francis has voiced his staunch opposition to a US-led strike on Syria, calling for reconciliation in Syria on Saturday as he led a mass "peace vigil" on St Peter's square, and as millions of Catholics worldwide were joined by other faiths in a day of fasting and prayer.
"In beloved Syria, in the Middle East, in all the world, let us pray for reconciliation and peace, let us work for reconciliation and peace," the pontiff told tens of thousands who had gathered on the square for the four-hour event, with smaller gatherings held in churches, mosques and synagogues around the globe.
Francis called for a "cry for peace" from humanity, firmly opposing all fighting in Syria, including the proposed military strikes against the Syrian regime being pushed by the United States and France.
A "limited" campaign of punitive strikes against the Assad regime is being pushed the US and some of its allies in response to the use of chemical weapons by government forces which are reported to have killed over 1,000 people, mostly civilians.
US President Barack Obama has been advocating for the use of force in response to what some analysts see as a dangerous precedent - the breaking of the "international norm" against using chemical weapons.
But the pope rejected such arguments, taking a markedly pacifist tone.
"War always marks the failure of peace, it is always a defeat for humanity," he declared
Earlier in the week he wrote to leaders of the G20 top world economies meeting in Saint Petersburg, Russia, urging them to "lay aside the futile pursuit of a military solution".
Vatican officials have warned international armed intervention could escalate the war into a wider conflagration that would further harm Christian minorities in the Middle East.
Indeed, the appeal has been particularly well received by Christian minorities in the Middle East, where often-divided leaders have been united in their concern about a possible spread of the Syrian conflict and the rise of radical Islam. Christian communities across the region have seen an upsurge in violent and deadly attacks by Islamists, including in Iraq, Syria and Egypt. many Christians fear that the significant presence of Al Qaeda-linked Islamists within the Syrian rebel movement could spell disaster for Syria's Christian minorities in the event of a rebel victory.
The Syrian conflict has killed an estimated 110,000 people since it erupted in March 2011, and the United Nations estimates two million refugees have fled the country.
The pope has repeatedly called for immediate peace negotiations and a process of reconciliation, as well as more humanitarian efforts to help civilians.
As US President Obama embarks on a campaign to persuade Americans to back military intervention, the Catholic Church, which counts 1.2 billion faithful worldwide, has is mobilizing itself to oppose strikes, spreading the pope's message through homilies in churches as well as through social media.
In a tweet from his @pontifex account on Saturday the pope urged his followers to "Pray for Peace!" The Vatican has even issued instructions for Catholic parents to prepare "sober" family meals with children and grandparents on Saturday that would be "rich in words".
The Vatican's Osservatore Romano daily published an interview with an Italian nun living in Syria who said fasting and prayer could "make one listen to a deeper wisdom".
When he announced the initiative on Sunday, Francis urged Christians from other denominations, faithful from other religions and atheists to join in.
The patriarch of Costantinople, Bartholomew I, spiritual leader of the world's Orthodox, also backed the call, while in France, Muslim faithful at the Great Mosque of Paris held prayers for peace on Friday.
Chief Rabbi of Rome Riccardo Di Segni said the Jewish community was also "in harmony" with the Vatican.
In Lebanon, the vice president of the Shiite Higher Council, Sheikh Abdel Amir Qabalan, voiced support, as did Christian leaders across the Balkans and in Latin America.
In Syria as well, Sunni Muslim leader, Grand Mufti Ahmed Badreddin Hassoun, called for Syrians to join in the prayers. However, in contrast to the pope's pacifist tone, Hassoun - a staunch supporter of Syrian President Assad, despite the tendency of most Syrian Sunnis to oppose the regime - has previously threatened to launch a suicide bombing campaign in Europe and the United States in the event of western military intervention.
"The moment the first missile hits Syria, all the sons and daughters of Lebanon and Syria will set out to become martyrdom-seekers in Europe and on Palestinian soil. I say to all of Europe and to the US: We will prepare martyrdom-seekers who are already among you, if you bomb Syria or Lebanon," he announced in a 2010 pubic address, aired on Syria News TV and translated by MEMRI (Middle East Media Research Institute).
Traditionally pacifist and anti-clerical groups, like the Radicals and the Left, Ecology and Freedom party in Italy, have also supported the pope's appeal.
The pope's call is not unprecedented - previous popes have appealed against the Iraq war, the conflicts in the Balkans and the Vietnam War - but it is nevertheless relatively unusual.
The last time the Vatican called a similar day of prayer and fasting was under late pope John Paul II in the wake of the September 11, 2001 attacks on the United States.