Myanmar's largest non-state army has upped its persecution of Christians, detaining pastors and destroying churches in areas bordering China and Thailand in Shan state, a new report has revealed.

Asia Times reports that the China-backed United Wa State Army (UWSA), a 30,000-strong ethnic armed group comprising the military wing of the United Wa State Party (UWSP), recently released a six-point statement instructing all of its military officers and administrators to "find out what the [Christian] missionaries are doing and what are their intentions."

The Chinese language statement also vows to punish any local administration cadres who support missionary activities, bans the construction of new Christian churches, and requires that priests and workers in existing churches must be local not foreign.

Additionally, the announcement bans religious teaching in schools in the Wa Hills area and UWSP functionaries are no longer allowed to be members of any "religious organizations."

Rev. Soe Naing from the Catholic Clergies Group told Radio Free Asia that Christians have already been targeted by the new order.

"We have heard that the UWSA has called and questioned clergy members about whether they are doing development work or persuading people to convert to Christianity," he said.

"If an individual or an organization builds a church in any area, they investigate to see whether it is being built because it is in a Christian community or whether it is being built to proselytize to get people to convert to Christianity," he continued, adding that so far, no arrests have been made.

Nyi Ran, a UWSA communications official at the army's office in the town of Lashio in Shan state, told RFA that Wa military leaders believe there are "religious extremists" in Wa territory, including missionaries who have not obtained official permission and clergy members who are operating outside the law.

UWSA soldiers have already apprehended "suspects" and are questioning them, he added.

American evangelical missionaries converted some Wa to Christianity around a century ago. Currently, Christians comprise about 30 percent of the 450,000 Wa.

The announcement comes just after John Cao, an ethnic Chinese pastor and permanent US resident of the state of North Carolina, was arrested in China in March for illegally crossing the Sino-Myanmar border. The pastor, who helped build 16 schools that serve around 2,000 children in the Wa Hills area, was sentenced to seven years in prison on immigration-related charges.

Cao's wife, Jamie Powell, reportedly said her husband, who was a prominent figure in China's illegal "house church movement," "was shocked by the poverty he saw" in the Wa Hills, which straddle the border between China and Myanmar. He saw "children without clothes" and a "makeshift school with a pigpen adjacent to the classroom."

The Asia Times points out that "while there is no reason to believe that Cao was more than a philanthropic church worker," the "Chinese as well as the UWSP may see the emergence of faith-based organizations and movements as a challenge to their authority."

In August, the U.S.-based persecution watchdog group ChinaAid launched an official White House petition urging the release the North Carolina pastor.

"While working to build schools for impoverished children in Myanmar, John was detained at the Chinese border on March 5, 2017. Twenty days later, he was charged with 'organizing illegal border crossing,' despite the fact that he had used the same route between China and Myanmar for this humanitarian work for years," explains in the We the People website petition.

"In three years, John helped build 16 schools that serve more than 2,000 children. He was unfairly sentenced to seven years in a Chinese prison."

The text calls on America to "pressure the Communist Party to unconditionally release Pastor John Cao and allow him to return home to America to see his wife and sons again."

As ChinaAid also states on its website, it wants the White House to take action on behalf of Cao to "uphold its commitment to religious freedom, human rights, and rule of law."