China has restricted the publication of academic research on the origins of the coronavirus, according to a central government directive and notices published by two Chinese universities.

The new guidelines require that all academic papers on the coronavirus undergo additional vetting before being submitted for publication, according to CNN. Studies on the origin of the virus also must be approved by central government officials, said the notices, which have since been removed from the web.

The increased scrutiny appears to be another attempt by the Chinese government to control the narrative about the coronavirus. China has been accused of concealing the extent of the outbreak.

"I think it is a coordinated effort from [the] Chinese government to control [the] narrative and paint it as if the outbreak did not originate in China," said a Chinese researcher who spoke to CNN on the condition of anonymity out of fear of retaliation." And I don't think they will really tolerate any objective study to investigate the origination of this disease."

The researcher said the extra scrutiny was only being applied to research on the coronavirus, not other subjects.

The virus has killed more than 100,000 people and sickened nearly 2 million people since it emerged in the Chinese city of Wuhan late last year.

Scientists have said the virus likely originated in bats and linked it to a market in Wuhan.

Chinese officials have engaged in an effort to claim that the virus originated in the United States and was brought to China by the U.S. military, which the U.S. has sternly disputed.