BEIJING -- China arrested 17 people suspected of spreading pornography on social apps amid its ongoing "Internet clearing" campaign, authorities revealed on Monday.

They were captured in five cases from late December to the end of April, including a woman, who has been released on bail due to pregnancy, the National Office Against Pornographic and Illegal Publications said in a statement.

The suspects stored a large quantity of pornographic videos and pictures on cloud storage systems developed by Internet giants Baidu and Qihoo 360 and sold access to the cloud accounts and passwords via popular social networks and messaging services, including WeChat and QQ, the office said.

In one case, a suspect surnamed Xie uploaded more than 4,200 video files to Baidu and 360 cloud storage services and gained profits of more than 50,000 yuan ($8,000) by sharing the accounts. Xie will stand trial.

The office said it will focus on regulating social apps and cloud storage services in the next two months and will severely punish Internet companies that fail to clear up illegal content.

It fined Baidu more than 210,000 yuan in March for spreading obscene and pornographic novels via its apps. Dating app MoMo was also fined 60,000 yuan in March and ordered to shut down group chats with overt sexual topics.