The escalating crisis in Hong Kong is a reflection of the "desperate cry for freedom in mainland China", Release International has said. 

It is calling on China to grant freedom of religion to Christians in the mainland who are experiencing increasing persecution. 

The organisation, which supports persecuted Christians worldwide, said that persecution in China has reached new heights since the tightening of religious restrictions in 2018. 

"Release partners say persecution has reached a peak not seen since the bad old days of the Cultural Revolution. Release is calling for those laws to be repealed," it said. 

The Regulations for Religious Affairs came into force in February last year supposedly to "protect citizens' freedom of religious belief" but have had the opposite effect, with pastors reporting a crackdown.

Until now, state interference was directed mainly towards unregistered 'house' churches but since the regulations came into force, registered churches have also been targeted. 

Under the regulations, religious teachers and staff members must report to local religious affairs departments who have the power to decide whether venues can be used as places of worship.  Donations amounting to more than 100,000 yuan (around $15,900) must be examined and approved by the religious affairs departments.

The application of the regulations has proved to be broad in practice. According to Release International, during the raid of one church in Guizhou province, when churchgoers asked what law they had broken, they were told: "It is illegal for you to teach your children to sing hymns and to spread [Christian] thoughts."

Release CEO Paul Robinson said: "Freedom of faith is guaranteed under Article 36 of the Chinese constitution. But in practice, the authorities bulldoze churches, tear down crosses and imprison pastors. Lawyers who speak up for them in the courts simply disappear. And it's getting worse.

"The authorities have labelled some Christians as belonging to 'evil cults' and have banned people from holding prayer meetings in their homes. If those prayer groups continue, the hosts risk having their houses demolished or taken from them.

"China has also banned Christians from sharing religious messages with anyone under 18 and has installed face-recognition cameras in churches to spy on congregations and preachers.

He said the protests in Hong Kong are connected to the situation on the mainland. 

"The scenes unfolding on the streets of Hong Kong reflect the desperate cry for freedom in mainland China," he said.

"Those cries for freedom are being met with tightening control." 

In light of the recent crackdown on both registered and unregistered churches, he added: "No wonder the people of Hong Kong see the writing on the wall."

Release revealed that it faced challenges this week when attempting to submit a petition calling for religious freedom to the Chinese Embassy in London.

Chinese officials turned down the organisation's request for an appointment with the ambassador to explain its concerns and refused to accept the petition in person supposedly on the grounds of security, requesting that it be sent by post instead. 

"And that we will," said Release spokesman Tom Hardie.

"We will make sure that China receives every single signature. They need to understand the depth of the feeling of Christians in the UK who will not stand by silently and let the persecution continue." 

Mr Robinson added: "Release International's message to China is: 'Christians are not a threat to the order and prosperity of their country. They love their land and pray for their government. Give them the freedom they long for and deserve.'"

There are increasing fears that China will resort to a Tiananmen-style crackdown on the Hong Kong protesters amid reports that PLA troops have been amassed at the border and begun military parades.

Protests have brought the airport and sections of the city to a standstill as hundreds of thousands of people have turned out over the last 10 weeks to protest the controversial extradition bill that would see some people sent to the mainland for trial. 

The bill, which chief executive Carrie Lam said was "dead", has not been fully withdrawn from the legislative agenda - a key demand of the protesters. 

The rhetoric coming from Beijing has hardened in recent days, with officials likening the protesters to "terrorists", while Chinese state media has suggested violent means to return the city to peace. 

The overseas edition of the Communist Party's official People's Daily newspaper said: "Using the sword of the law to stop violence and restore order is overwhelmingly the most important and urgent task for Hong Kong!"

Benedict Rogers, of Christian Solidarity Worldwide, said he fears a military putdown of the protests on a par with the deadly show of force in Tiananmen Square in 1989. 

"There are, in reality, only two ways to resolve the impasse in Hong Kong right now. One is, God forbid, a Tiananmen-style crackdown, which we are already beginning to see in embryo with the police's widespread use of teargas, batons, beatings, shotgun triggers pulled, and Triad gangsters mobilized," he said, writing in UCA News.

"Let us hope that neither [President] Xi Jinping nor [Hong Kong Chief Executive] Carrie Lam allows for the deployment of the trigger-happy [People's Liberation Army] PLA, which would result in a massacre that would not only slaughter the individuals concerned — hundreds of them — but kill off the hopes of Hong Kong remaining an international financial center and an open city in the region.

"Such a massacre would be the slaughter of Hong Kong itself, it's very raison d'etre, its meaning, soul and being."