China Business News and Hong Kong's South China Morning Post said some of the accounts closed were run by widely-read columnists like investigative journalist Luo Changping, some of which have hundreds of thousands of subscribers.
The accounts were closed on Thursday, the newspapers said, the same day Premier Li Keqiang held a news conference in Beijing marking the end of the yearly meeting of parliament.
Tencent, responding to the reports, said that the company was committed to combatting the transmission of pornography, rumours and violence.
"As part of the commitment to providing quality user experience on Weixin in China, we continually review and take measures on suspicious cases of spam, violent, pornographic and illegal content," said Jerry Huang, a Shenzhen-based spokesman for Tencent, using the Chinese name for WeChat.
"We also welcome users to report to us online or through our 24-hour hotline."
Tencent added on one of its official microblogs that if banned content appeared onWeChat then the company would "strike hard and deal with it".
WeChat, meaning "micromessage", leapt from 121 million global monthly active users at the end of September 2012 to 272 million in just a year.
It has quickly become the news source of choice for savvy mobile users in China, where a small army of censors scrub the country's Internet of politically sensitive news and "harmful" speech.
Unlike popular microblogging services such as Sina Corp's Sina Weibo, where messages can reach millions of people in minutes, WeChat allows users to communicate in small, private circles of friends, and send text and voice messages for free - a big part of its success.
China has moved to rein in WeChat before.
In January of last year, users were blocked from sending messages containing the characters for "nanfang zhoumo", Chinese for "Southern Weekly", a newspaper that was in open revolt against press control in Guangdong province.
Last year, China's Communist Party renewed a heavy-handed campaign to control online interaction, threatening legal action against people whose perceived rumours on microblogs such as Weibo are reposted more than 500 times or seen by more than 5,000 people.
Rights groups and dissidents have criticised the crackdown as another tool for the party to limit criticism and to further control freedom of expression.
The government says such steps are needed for social stability and says every country in the world seeks to regulate the Internet.
© Thomson Reuters 2014