Reporters Without Borders (RSF) has urged Prime Minister Dr Mahathir Mohamad to not go back on his promises on guaranteeing freedom of the press.

In an open letter to Mahathir, the journalist group's secretary-general Christophe Deloire said RSF will be closely monitoring the fate of the promises delivered by the prime minister.

"In the manifesto of Pakatan Harapan, you pledged that your government would guarantee press freedom, and reiterated this promise in your statements during the election campaign.

"You undertook to repeal all draconian laws that have imposed a climate of oppression and self-censorship within the media for decades, (and) to create an independent media regulatory body to ensure that the government would no longer be able to influence and manipulate public broadcaster RTM and government news agency Bernama," Deloire noted.

However, Mahathir reneged on these promises when he said that the Anti-Fake News Act (AFN) will not be repealed, Deloire added.

"Almost immediately after forming your government, you went back on your campaign promises. Although you were yourself one of the first victims of the Anti-Fake News Act, you announced a few days ago that it would no longer be repealed. Despite protests from journalists and representatives of parties in your alliance, you said that it would instead be amended in order to define the concept of false information more clearly. You also said that 'there are limits' to press freedom like everything else.

"We are extremely disturbed by this turnaround," said Deloire, further reminding Mahathir as the prime minister, the latter has a duty to keep to promises and respect the undertakings given.

Following backlash to his remark that the AFN law will be 'studied', Mahathir clarified that the review is important so he could understand the law before scrapping it.

The AFN Act 2018, enacted in April by the previous BN government, carries a jail term of up to six years and a fine of up to RM500,000.

Critics have said that the law does not clearly define what is considered fake news, and could be used by the government to clamp down on dissenting views.

Deloire also "reminded" Mahathir of the various way dissent was suppressed during his 22 years of previous rule, between 1981 and 2003.

"You ordered the closure of newspapers, imprisoned your critics, including journalists, harassed independent media outlets and used the Internal Security Act to force the media to censor themselves.

"As you begin a new term as prime minister after remarkable elections, RSF will be paying close attention to the fate of the promises you gave, to guarantee freedom of the press. We hope that your return to office will mark an end to the reign of self-censorship and an end to persecution of the media and the freedom to inform in Malaysia."

Malaysia ranks 144th out of 180 countries in RSF's 2018 World Press Freedom Index.