Chinese authorities closed down a prominent house church in the country's coastal Zhejiang province for organizing "Christian activities without permission" and attempted to replace crosses with the national flag amid an ongoing crackdown on believers.

According to China Aid, Chinese authorities have increased pressure on churches in the area ahead of the annual G20 summit, held in Hangzhou, Zhejiang from Sept. 4-5. During this meeting, world leaders, including U.S. President Obama, will gather to discuss key issues of the global economy.

Zhejiang authorities have reportedly been preparing for this meeting as early as February, including a close monitoring of hotels, restaurants, churches, temples, and a crackdown on house churches unapproved by the government.

Recently, officials recently raided a 2,000-member house church in Hangzhou that is affiliated with Watchman Nee's "Little Flock" Local Church movement. While the house church has been in existence for more than 40 years - even gathering during Mao Zedong's oppressive Cultural Revolution -  local neighborhood committee and police station issued a notice that prohibited all future meetings.

In addition, eight officials from the religious affairs bureau and its subdistrict office raided the church to take pictures and disperse the service, forbidding the church from meeting further. Several other house churches in the area also reported authorities forcing meetings to stop.

The report notes that authorities have also been targeting churches outside of Hangzhou, including Qibao Church, which is located in Wenzhou - known as China's "Jerusalem" due to its large Christian population. A local Christian told the outlet, "After removing some church crosses, they wanted to put up the [national flag], but [some] people did not let them. It was not possible for [officials] to erect some flags. Our church doesn't have one and neither does our rooftop. [The authorities] are picking quarrels over nothing."

Zhou, another Christian from Hangzhou, told the outlet he fears the government will require house churches to stop meeting altogether.

The closure of the church is only one of the latest in the government's attempts to clamp down on Christianity as the Communist Party grows increasingly suspicious of the influence of the religion, which is experiencing significant growth in the country. The Chinese government puts the number of Christians at 23 million, and the number of Catholics at more than 5 million.

In addition to church closures, over the past year, up to 1,700 churches have been demolished or had their crosses removed in Zhejiang alone province, and a significant number of pastors and human rights lawyers have been arrested and imprisoned.

In light of such ongoing persecution, China Aid president Bob Fu accused the Communist regime of making a mockery of "basic justice" and urged the U.S. leaders to use the upcoming G20 summit to urge Chinese leaders to release those imprisoned and end persecution against Christians across the country.

"With next month's G20 summit being held in China, we urge the United States to ask the Chinese government to immediately release those who were sentenced and those who are about to be tried in the next few days, including attorney Li Heping," Fu wrote. "The Chinese regime should also immediately stop mistreating their family members, including their wives and children."