Chinese president Xi Jinping has a 'particular animosity' against Christians, according to the head of a persecution watchdog.

Speaking during a discussion on religious oppression sponsored by the Heritage Foundation in the US, Bob Fu, founder of China Aid, said Xi views Christianity as a threat to his rule, according to the Gospel Herald.

However, Fu said persecution 'will only help accelerate the growth' of the faithful.

There are now more than 38 million Protestant Christians in China and Fu said the number of those persecuted had 'dramatically increased'.

He said the state was forcing churches to install facial recognition systems in order to identify who attended services. Every church building, he said, was 'forced to put a sign [up] banning children, students, civil servants, military personnel, and communist party members from entering'.

Unofficial 'underground' churches were seen as a particular threat, he said, but even attendance at official churches had increased.

'You can see that he [Xi] has particular animosity against Christianity in particular,' Fu said.

Kristina Arriaga, the vice chairwoman of the US Commission on International Religious Freedom (USCIRF), said: 'A lot of things have happened in the last few months that are very troubling for the future of Christianity in China.

'The situation for Christians there is dire... One thing we know for sure is that the persecution [against] Christians has doubled in intensity.'

Xi, who has recently succeeded in removing the term limits that would have prevented him from serving again as China's president, has cracked down on Christianity and asserted state control over religion. His government is locked in a struggle with the Vatican over the appointment of Catholic bishops, with neither wishing to cede control over who serves Catholics in China. For Protestant Christians, church demolitions have increased and in some parts of the country Christians face increasing harassment.