Journalists have been forced to temporarily take down articles critical of powerful oil lobbyists due to the exploitation of US copyright law, according to a new report.

At least five such articles have been subject to fake copyright claims, including one by the respected South African newspaper Mail & Guardian, according to the Organized Crime and Corruption Reporting Project (OCCRP).

The claims - which falsely assert ownership of the stories - have been made by mystery individuals under the US Digital Millennium Copyright Act (DMCA), a law meant to protect copyright holders.

Just last month, three separate false copyright claims were made against Diario Rombe, an investigative news outlet that focusses on Equatorial Guinea.

The articles under attack are about the president of Equatorial Guinea's son, Gabriel Mbaga Obiang Lima, and his close associate, Cameroonian businessman and lawyer NJ Ayuk.

The OCCRP claimed in a report published on Wednesday that the DMCA process was often abused by "unknown parties" who create backdated fake articles to target critical news reports.

Under the US law, any online author saying that their content has been stolen can seek to have what they claim is the infringing material "taken down" by triggering a formal legal process through web servers who host the material.

The process differs depending on the server provider, but it can mean content is removed from the web for weeks while the genuine author proves their credentials.

The OCCRP is yet to discover who is behind the attacks, however all the stories were critical of NJ Ayuk.

NJ Ayuk, also known as Njock Ayuk Eyong, is the CEO of African law firm Centurion Law Group and the founder of the African Energy Chamber (AEC). He is also an outspoken advocate of the oil industry in Africa.

Mr Ayuk has a close relationship with the other subject of two of the stories, Gabriel Mbaga Obiang Lima. Mr Obiang Lima was Equatorial Guinea's Minister of Mines and Hydrocarbons until a recent cabinet reshuffle.

Mr Ayuk has issued press releases from Centurion Law Group and the AEC which publicly attack journalists criticising his oil lobbying activities and questioning his close relationship with Mr Obiang Lima.

The first known false copyright claim to target reports on Mr Ayuk was made in 2019, following the publication of an article in South Africa's Mail & Guardian (M&G) titled Fraudster named in SA's oil deal.

The story examined Mr Ayuk's involvement in an oil deal between South Africa and South Sudan worth hundreds of millions of dollars. It revealed that Mr Ayuk was convicted of fraud in the US in 2007 after pleading guilty to illegally using the stationery and signature stamp of a congressman to obtain visas for fellow Cameroonians.

After the story was published, the M&G's web server Linode was contacted by an "Ian Simpson", claiming he was the original author of the piece. Linode took down the news outlet's entire website for a morning in response to the complaint.

M&G investigated and found that the US address given did not exist and that there were no other traces online of this alleged author. M&G concluded that "Simpson" and his article were fakes but Linode forced the newspaper to take down its article about Mr Ayuk before it would restore the rest of the M&G website.

Writing about the takedown, the M&G called this a "censorship attack".

Last November during the UN's climate summit COP27, UK-based Climate Home News published an article about Mr Ayuk launching a partnership with two UN agencies called UN gives platform to convicted fraudster lobbying for African gas.

The article highlighted the role of the African Energy Chamber in the UN's flagship Team Energy Africa private investments initiative and referenced Mr Ayuk's US fraud conviction.

The UN cancelled the initiative following the publication.

Two weeks later, Climate Home News' server AWS received copyright claims on both articles from "Thomas L Pierce" and "Marcus A Webre". The OCCRP was unable to trace the complainants, and emails to their provided addresses went unanswered.

AWS told Climate Home that it might have to take action against Climate Home News unless it could confirm that the matter had been successfully addressed.

Climate Home editor Megan Darby removed the articles while addressing the false claims with AWS. It took several weeks before Climate Home was able to reinstate the articles.

Ms Darby told the OCCRP: "These bogus allegations look like a devious tactic to suppress independent journalism."

Earlier this year, unknown parties filed three complaints against independent investigative outlet Diario Rombe over articles authored by them. Two were with its server Cloudflare and one with Google. They targeted two 2021 articles published in collaboration with OCCRP which were critical of Mr Ayuk and his relationship with Mr Obiang Lima.

All three complaints appear to have originated from South Africa. The OCCRP said that it could not establish whether the purported claimants "Lavino Siqueira" and "Mark E Bailey" were real people, and again, emails to their addresses went unanswered.

Google removed the second article from its search results. It reinstated the piece only after Diario Rombe filed a so-called "counter-notice".

Diario Rombe editor Delfin Mocache Massoko said: "These copyright complaints for a small outlet without funds like Diario Rombe do huge damage to our work. I believe that the author has a single mission, to eliminate all negative information about Mr Ayuk and Lima from the internet."

When contacted by the BBC, Mr Ayuk strongly denied corruption allegations and said he, the AEC and Centurion Law Group denied the allegations made by the OCCRP including in relation to fake copyright claims.

Gabriel Mgeba Obiang Lima did not respond to requests for comment at time of publication.

The OCCRP contacted AWS, Google and Cloudflare for comment on the bogus copyright complaints, but they did not respond.