China pastor Gu Yuese investigated for corruption

China has restricted the use of crosses outside Protestant and Catholic churches in some provinces

A prominent pastor in China, Gu Yuese, is being investigated for corruption, according to local church authorities in Zhejiang province.

Mr Gu, the head of one of China's biggest state-sanctioned churches, is accused of embezzling funds.

A group of Hong Kong-based Christians have since alleged his probe is linked to his open opposition to a government crackdown on Christian activity.

China is officially atheist but says it guarantees religious freedom.

However, all churches have to be approved by the state and authorities keep a close eye on their activities to contain their influence.

'Political revenge'

Mr Gu is the pastor of the Chongyi Church in Zhejiang, which has thousands of followers. The church could not immediately be reached for comment.

The local chapters of state-backed church authorities China Christian Council and Three-Self Patriotic Movement posted similarly-worded statements on their websites on Friday about Mr Gu's arrest.

They said they had 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".

This church in Zhejiang was demolished in 2014 after officials said it was an illegal structure

However, Bob Fu, of the US-based Christian human rights group China Aid, told the BBC that the charges were "political revenge" for Mr Gu's "disloyalty to the Chinese Communist Party's religious policy" by opposing the government's forced demolition of crosses on churches.

"In the past two weeks 18 crosses were removed and destroyed... Overall at least 1,800 crosses of churches were demolished since the campaign started," he said.

Zhejiang, a province located in the south east of China, is home to many churches, particularly in the city of Wenzhou.

The city saw a crackdown on displays of crosses in 2014, and again last year - a policy Mr Gu had openly opposed.

A group of about 40 Christians in Hong Kong, some of whom are church leaders, also alleged in an open letter to the media that Mr Gu's arrest was connected to his opposition to government efforts to contain churches in the province.

They said that after local churches objected to the tearing down of crosses last July, authorities began investigating Chongyi Church "in order to cook up charges and suppress suspected dissidents".

In August 2015, pastor Bao Guohua (R) and his wife Xing Wenxiang (L) were also detained on suspicion of embezzlement

In August last year pastor Bao Guohua, his wife and several church employees were detained in Zhejiang, and accused of embezzlement as well as disrupting social order.

Their church's lawyer told the BBC at the time they were being punished for protesting against the removal of their church cross.

Authorities have justified the tearing down of crosses, and in some cases the demolition of church buildings, by saying they were illegally constructed and broke planning rules.

But rights groups say such actions are an effort to rein in their power and run contrary to the guarantee of religious freedom in China's constitution.