The pastor of China's largest Protestant church, who was removed from his position without warning by the authorities, has been accused of embezzling church funds and detained in a so-called 'black jail'.

Pastor Gu Yuese, senior minister of the 10,000-member Chongyi Church, was ejected from office last week by the official Three-Self Patriotic Movement (TSPM) and the China Christian Council.

According to the religious liberty group China Aid, authorities have accused him of embezzling 10 million yuan (£1 million).

China Aid told Christian Today that Gu's entire leadership team at Chongyi Church had been ordered to leave and assigned to different congregations. A pastor approved by the state-backed China Christian Council has taken control of the church and preached yesterday. All churches have been ordered to install a Chinese flag on their buildings. 

The local chapters of the China Christian Council and TSPM posted similarly-worded statements on their websites on Friday about Gu's arrest.

They claimed to have learned in "recent days" that Mr Gu was "being investigated because of suspicions of economic issues, including embezzling money", adding that the matter had "to do with one individual's behaviour".

Gu had publicly opposed the government campaign to tear down the crosses that identify church buildings, leading to speculation that his removal was connected to his outspoken activism.

China Aid Founder and President Bob Fu told Christian Today Gu's arrest and the accusations against him were "political revenge" for his public opposition to the removal of crosses. He said Gu's fate was "sealed" when he spoke out.

"Rev Gu's conscientious act, broadly welcomed by the Chinese and international Christian community, was certainly perceived as 'crossing the red line' by the Chinese Communist Party (CCP) leadership," he added.  

Fu said that Gu's treatment was designed to intimidate other Christian leaders within the official TSPM churches into keeping silent about the removal of crosses.

"In the past two weeks 18 crosses were removed and destroyed. Thirteen of them happened last week alone," he said. "Overall at least 1,800 crosses were demolished since the campaign started.

"I have no doubt President Xi is behind this. Rev Gu will eventually [be] indicted and, depending on how his public confession will go, he will be treated like a 'criminal'."

Gu would be "thoroughly isolated and interrogated" until he was publicly indicted, Fu said. 

According to China Aid, Gu has been placed under "residential surveillance in a designated location", code for a detention centre operating outside the legal system, or 'black jail'. Family members believe that the pastor's wife, whom they have been unable to contact, was also taken into police custody.

Fu said: "His arrest marks a major escalation in the crackdown against those who oppose the forced demolition of crosses. He will be the highest-ranking national Church leader arrested since the Cultural Revolution."

A group of about 40 Christians in Hong Kong have alleged in an open letter to the media that Gu's arrest was connected to his opposition to government efforts to contain churches in the province, reports the BBC.

After Gu's dismissal he and his wife Zhou Lian Mei, who teaches Bible classes at the church, issued a statement thanking the congregation for its support and affirming their commitment to the church.

They said: "Regardless of how the situation will be after this, we will inevitably continue serving at Chongyi Church if there is no other guidance from the Lord himself! Of course, the manner [of service] may change, but our love of the Lord and his flock will never change, because we are the Lord's servants! Thank God!"

The statement continued: "Increasingly, we feel God's good intentions in this storm. It will refine every impurity in our ministry team to the greatest extent and compel us to love the Lord and people more purely."