WASHINGTON - Uganda is ramping up efforts to curtail online content deemed immoral or hateful, a move critics say will silence dissent.

Since March 2018, the Uganda Communications Commission, a state regulator, has required certain online publishers to register and pay a fee of $20 per year.

Now, the government is expanding its enforcement of the regulation, levying the fee on news organizations and social media influencers with large followings, including some journalists, celebrities, musicians and athletes.

The UCC calls these people "data communicators" and will be looking at media sites, including Twitter, Facebook, Instagram and YouTube to determine which users will be affected.

Catherine Anite, executive director of the Freedom of Expression Media Hub, told VOA's Nightline Africa that the registration requirement curbs free speech.

"It's a very restrictive regulation," she said. "The freedom of expression is an essential right, and it is the cornerstone of any democratic society, which I believe Uganda is, because we have ascribed to these national, regional and international freedom of expression laws."

Anite pointed to Article 29 of Uganda's constitution, which protects freedom of speech, freedom of the press and freedom of belief. She said this should give Ugandans wide latitude to express themselves in any media.

"Uganda is a free society. Uganda is [a] democratic society," she said. "So, if the constitution gives the right to enjoy freedom of expression, there shouldn't be the clawback clauses that come in the form of policies and other restrictive laws."

The expansion of the law comes one week after political activist Stella Nyanzi was sentenced to 18 months in prison for writing a crude poem about Ugandan President Yoweri Museveni's deceased mother.

The group Unwanted Witness, which monitors digital rights, reported that 33 Ugandans have been interrogated by police or charged with making impermissible online communications between 2016 and 2018, according to Reuters.

Last year, the government introduced a tax on social media usage, charging 200 shillings - about $0.05 cents per user per day, Reuters reported.

UCC head of public relations Ibrahim Bbossa said the regulatory body hopes to make publishers and individuals with large online followings mindful of the need to uphold public morality and peace.

He said registering users is the first step to responding in the event of a problem.

"As UCC, it is upon us to put into implementation these laws so that, just in case of any problems that arise, we are able to come up with resolutions," Bbossa told Uganda's Daily Vision "Online publication can lead to circumstances like inciting the public, misinformation, and at times, theft."