KUALA LUMPUR (Reuters) - Malaysia blocked access to a widely read news portal on Thursday, the latest in a series of clampdowns on media organizations that have published reports critical of the government and Prime Minister Najib Razak.

The Malaysian Communications and Multimedia Commission (MCMC) said in a statement that the Malaysian Insider had breached laws under the Communications and Multimedia Act 1998.

The Malaysian Insider has published several reports on the scandal around 1Malaysia Development Berhad (1MDB) and investigations into $681 million deposited into Prime Minister Najib’s personal accounts.

The 1998 act prohibits using a website to publish “any comment, request, suggestion or other communication which is obscene, indecent, false, menacing or offensive in character with intent to annoy, abuse, threaten or harass another person”.

“The MCMC reminds news portals not to spread or publish articles where the facts have not been proven. This is because such actions could create confusion and spark unintended situations,” the commission said, adding that the block arose from complaints and information from the public.

No further details were given.

Najib has denied any wrongdoing over the money transferred into his account, saying that the funds were a political donation and that nothing was taken for his personal gain.

Malaysia’s attorney-general closed all investigations into Najib last month, after reviewing investigation reports from the Malaysian Anti-Corruption Commission (MACC).

The Malaysian Insider’s editor and chief executive Jahabar Sadiq said the portal had yet to receive an official notice from the MCMC on the blockage.

Jahabar, along with two other editors of the website, was arrested last year on suspicion of sedition. They were later released on bail and have not been charged.

Last year, Malaysia blocked the U.K.-based portal Sarawak Report, saying it had violated a local internet law.

It also suspended two financial newspapers, the Edge Weekly and the Edge Financial Daily last year for reporting on alleged graft at 1MDB. Both papers are owned by The Edge Media Group, which also own The Malaysian Insider. The suspension was lifted in September after an order by the Malaysian High Court.