ROME — The Vatican said on Saturday that it had reached a “provisional agreement” with China on the process used to appoint bishops, a breakthrough after years of contentious negotiations on the management of Catholic leadership in the communist country.

The deal paves the way for bishops to be recognized by the Vatican and the Chinese government, a step toward ending the current system — one that has divided followers — in which some bishops are backed by only one side or the other.

The accord marks a potentially transformative step in relations between the world’s most populous country and one of the most powerful religious institutions. Some outside experts say the agreement could end seven decades of strain between the sides, opening the door for the possible resumption of diplomatic ties, which were severed in 1951.

Beijing and the Holy See have long been at odds on leadership of Catholics in China, where the government has appointed bishops and authorized which churches can operate. Their deal comes even as President Xi Jinping has tightened his grip on power, cracking down on freedoms and saying that any practice of religion must be “Chinese in orientation.”

For Pope Francis, the outreach to China has been perhaps his most ambitious diplomatic venture, an effort to broaden the appeal of a faith that has lost ground in much of the Western world and is dealing now with a global wave of sexual abuse cases. Catholicism is one of the five religions officially tolerated by Chinese leaders, but it has been steadily eclipsed in popularity by Protestant and evangelical denominations.

Francis will probably draw pointed criticism from many Catholic opponents of the deal, who say the church is eroding its credibility by compromising with an officially atheist country that has long targeted Catholics and others with surveillance and persecution.

Cardinal Pietro Parolin, the Vatican’s secretary of state, said the agreement reached on Saturday in Beijing “is of great importance, especially for the life of the Church in China.”

“What is required now is unity, is trust and a new impetus; to have good Pastors, recognized by the Successor of Peter — by the Pope — and by the legitimate civil Authorities,” Parolin said in a statement.

After announcing the agreement, the Vatican said it was lifting the excommunications of seven Chinese bishops ordained without papal approval. That concession, a central part of the agreement, means that all bishops in China are now recognized by the Vatican — and operating under the pope’s authority.

“Of course, this is not an accord that solves all problems of the church in China, but certainly it’s a historic step,” said Elisa Giunipero, director of the Confucius Institute at Milan’s Sacred Heart Catholic University.

The church in China has long been split between Catholics who swear allegiance to the Vatican and others who practice the faith in state-sanctioned churches supervised by the Chinese Patriotic Catholic Association.

Some church leaders have the backing of the Vatican but not of the Chinese government, meaning they operate furtively in unofficial churches. The agreement reached Saturday was not published, and neither the Vatican nor China said how the issue of those leaders would be addressed.

Estimates put the number of Catholics in China between 10 and 12 million. About half are affiliated with government-managed churches. Citing “Vatican sources,” Reuters said the deal gives the pope veto power in the naming of candidates for bishop.

“Pope Francis hopes that, with these decisions, a new process may begin that will allow the wounds of the past to be overcome, leading to the full communion of all Chinese Catholics,” the Vatican said in a statement.

The issue of bishop appointments has for decades been the main point of contention between the Vatican and China, which have negotiated since the 1980s to end the impasse. But those efforts have faced significant opposition, particularly from Catholics in Hong Kong, who say that Chinese Catholics have a right to practice their religion without the meddling of the Chinese government.

Cardinal Joseph Zen, the former bishop of Hong Kong, said earlier this year that “if the government is managing the church, it is not the Catholic Church anymore.”

Under Pope John Paul II and Pope Benedict XVI, the Vatican recognized some bishops appointed by the Chinese government. But the diplomatic efforts increased under Francis, continuing even as the church dealt with sexual abuse scandals.

Francis has talked about his wish to travel to China, and he spoke in a 2016 interview about the “greatness of the Chinese people.” At the beginning of the year, in a conciliatory move, the Vatican urged two bishops unsanctioned by the Chinese government to step aside in favor of figures with government backing.

“We don’t have to look at the agreement as a point of arrival, but as a starting point,” the Rev. Antonio Spadaro, a confidant of Francis, wrote in an op-ed in La Civiltà Cattolica, a Rome-based periodical. “The improvement of Chinese Catholic religious quality of life won’t be automatic. Challenges still remain, but of course the process is a positive factor for Chinese Catholics.”

The Vatican said its agreement with China “is the fruit of a gradual and reciprocal rapprochement” and includes a possibility for “periodic reviews of its application.”

The Chinese foreign ministry released a statement saying that “China and the Vatican will continue to maintain communications and push forward the process of improving relations between the two sides,” according to the Associated Press.

The accord is also a sensitive issue for Taiwan, which is viewed by China as a breakaway province. The Vatican is the only European state to maintain full diplomatic relations with Taiwan. Taiwan’s foreign ministry said in a statement that it had been assured by the Vatican that the deal with China would not affect diplomatic relations.

Stefano Pitrelli contributed to this report.