A lawyer from East China's Zhejiang Province sued the local publication watchdog on Monday after 14 books that he bought online and that were published by Taiwan or Hong Kong publishers - some of which are about the Bible, Marxism and North Korea - were confiscated on suspicion that they were "illegal publications."

Yuan Yulai, a lawyer at Zhejiang Zhixing Law Firm who has taken on several cases against government bodies, told the Global Times on Monday that he has filed his suit with the People's Court of the Beilun District in Ningbo, Zhejiang and will receive a reply within seven days.

"These books were published by Taiwan or Hong Kong publishers, and I bought them from a Chongqing-based Taobao store. They are not banned books," Yuan said.

In his suit, Yuan argues that if people from the mainland are forbidden from purchasing books published by Taiwan and Hong Kong publishers because such books are identified as illegal publications, cultural exchange between the Chinese mainland, Hong Kong and Taiwan will ultimately fail, hindering China's unification.

According to Yuan, five people including law enforcement officers from the culture, radio, television, news and publication bureau of Ningbo's Jiangdong district and local police officers came to his office on March 4 and informed him that books in an unopened package were illegal publications. Despite his protests, the officers opened the package and confiscated all 14 books.

The publication bureau's law enforcement officers confirmed with news portal sohu.com on Friday that they were involved in the case, noting that it was a "joint operation" with local police.

The officer said that their operation was based on regulations on publication management and that it is not yet clear whether the seized books are illegal. "These books will undergo professional identification, and the result will be released," he said.

Photos of the seized books presented by Yuan showed publications about North Korea  and others about the Bible, the Cultural Revolution and Nazi atrocities.

A search of Chinese e-commerce website taobao.com showed that some of these books were still sold on the platform as of press time.

Yuan demanded that the bureau return his books, saying that the officers had no right to forcibly examine his mail.

According to the Constitution, the freedom and privacy of Chinese citizens' correspondence are protected by law. No organizations or individuals may infringe upon the freedom and privacy of correspondence for any reason, except in cases where police or prosecutors are permitted to censor correspondence in accordance with procedures prescribed by law to meet the needs of State security or in the course of an investigation into criminal offenses.

Yuan is also known as an online celebrity who had over 20 million Sina Weibo followers before his account was shut down in late 2015. He started an online campaign in April 2013 encouraging people to stop visiting the town of Fenghuang, a popular tourist destination in Xiangxi Tujia and Miao Autonomous Prefecture in Central China's Hunan Province, after local authorities began charging entry fees to the town, prompting a backlash among local store owners.