BEIJING -- A total of 29 live streaming platforms have been investigated and punished for spreading pornography since the end of last year, China's anti-pornography office said Wednesday.

During a national campaign, operators of live streaming platforms were found to have profited through online pornography, according to a statement from the National Office Against Pornographic and Illegal Publications.

Anti-pornography offices at various levels have stepped up efforts to crack down on similar illegal online activities and cut the profit chain of illegal live streaming, it said.

Some of the suspects may face criminal charges.

In one case, 13 suspects were detained and 8 others captured by police in the provinces of Guangdong, Henan and Heilongjiang in July last year after they were found to have involved in illegal live streaming, according to the statement.

The suspects have been transferred to prosecution authorities, it said.

In another case, police in Wuxi city in east China's Jiangsu Province captured 52 suspects in September last year for organizing female anchors to spread obscene content through mobile apps.

The suspects made more than 3.5 million yuan (about $550,000), according to the statement.

Live streaming emerged in China in recent years, however, problems such as the streaming of obscenity, violence and other inappropriate content surfaced as the market has grown. Chinese authorities have intensified efforts to crack down on illegal online activity.