July 16 (Reuters) - Pope Francis on Friday overturned decisions by his two predecessors and re-imposed restrictions on the old-style Latin Mass preferred by traditionalist Roman Catholics, saying it was being exploited to divide the Church. Conservative groups reacted with dismay and anger to the latest episode of what some have dubbed the Church"s "liturgy wars". Some conservatives in the Church, particularly in the United States and some European countries, have used the Latin Mass as a battle cry in their general opposition to the reforms of the 1962-1965 Second Vatican Council, which included the introduction of Mass in vernacular languages. Before the Council, Catholic mass was an elaborate ritual led in Latin by a priest with his back to the congregation. Vatican II reduced the formality and had the priest face the faithful to pray in their local language. Traditionalists rejected the new style’s sing-along hymns and guitar music. Many missed the Latin rite’s sense of mystery and awe and the centuries-old Gregorian chant that went with it. Both former Pope Benedict and Pope John Paul had relaxed restrictions on the Latin Mass in an olive branch to conservatives, particularly in attempts to heal a break with the traditionalist Society of St. Pius X, whose founder Archbishop Marcel Lefebvre was excommunicated in 1988. In 2007 Benedict ruled that any Roman Catholic priest could celebrate the old Latin Mass without the specific permission from a bishop or from the Vatican that previously had been required. Among other restrictions, Francis" decree issued on Friday restored that obligation and said no new groups or parishes which are exclusively devoted to the old liturgy could be established. In an explanatory letter to bishops, Francis said the good will and leniency shown by his predecessors had been "exploited to widen the gaps, reinforce the divergences, and encourage disagreements that injure the Church, block her path, and expose her to the peril of division." Francis said some priests who insisted on using only the old Latin Mass did so to promote "unfounded and unsustainable assertions" that the Second Vatican Council had "betrayed the Tradition and the "true Church"". The Council"s documents opened the Church to the modern world, giving a larger role to lay people and started a dialogue with other religions, particularly Judaism. While former Pope Benedict made accepting the changes of the Council a condition for celebrating the old Latin Mass, many conservatives who prefer the old liturgy also openly reject the Council"s reforms. The traditionalist blog Rorate Caeli called the pope"s decision an "act of vandalism perpetrated by Francis" against his predecessor Benedict. In a commentary, the Latin Mass Society of England and Wales called it a "grave disappointment" and challenged Francis" supporters "to produce real evidence that the (Latin Mass) has undermined the unity of the Church."