A pastor in Hong Kong has been prosecuted in mainland China for printing Christian books and raising money, according to UCA News.

Rev Ng Wah disappeared in July and was arrested on the mainland, said Constant Kim, Wah's friend and a member of his Christian Church of Chinese Ministry.

Kim said: "It is political persecution. Some extreme leftist officials in Guangzhou did this."

The pastor is believed to have faced a fraud trial over funds totalling more than 100 million yuan (US$15.43 million).

He was tried with Lin Jingying, who organised an unregistered house church.

Ng Wah's colleague Rev Phillip Woo was told to stop preaching in mainland China by officials who accused him of violating the country's religious laws. He had posted messages on social media calling on Chinese Christians to come to Hong Kong for training.

Woo told ucanews.com the incidents showed China's religious situation "has tightened."

They are the latest in a series of imprisonments evidently illustrating China's harder line toward Christians. Pastor Gu Yuese, who opposed the demolition of churches and the removal of crosses in Zhejiang province, was imprisoned on similar charges of embezzlement but has just been released and placed under "residential surveillance".

According to China Aid, both Pastor Gu and Christian human rights lawyer Zhang Kai were released in advance of President Xi's visit to the US for the Nuclear Security Summit in Washington DC.

Also in China, Christian human rights lawyer Ni Yulan has been prevented from travelling to the US to receive an International Women of Courage Award. Ni, who has previously been imprisoned and tortured, was refused a new passport, apparently because of her connection with lawyers detained in a "crackdown" on July 9, in which more than 300 lawyers, activists, family members and associates were interrogated, detained, imprisoned and disappeared.