Malaysian Prime Minister Najib Razak has defended himself against a slew of criticisms over corruption scandals and a crackdown on civil liberties, brushing aside suggestions that he should step down.

‘I was elected by my party, and by the people of this country, to lead them. As such, I am answerable only to the people -- not to any one individual,’ Najib said in an interview on state-controlled television broadcast late Thursday night.  

Najib has come under fire over a state-owned investment company he launched, now mired in $11 billion of debt and allegations of fraud and huge sums of missing money.

His government -- long accused of using security laws to stifle dissent -- this week also triggered outrage by passing a tough anti-terrorism act allowing authorities to detain suspects without charge in the Muslim-majority country.

It also amended a sedition law -- used against dozens of government critics over the past year -- to provide a maximum 20-year jail term, up from three years.

‘Contrary to what some are suggesting, these laws will not be used against critics of the government,’ Najib said of the terrorism legislation, according to an English translation of his comments released by his office.

‘Rather, they will be an extra tool for dealing with the militant threat that all countries face.’

The prime minister was forced to respond after hardline former leader Mahathir Mohamad last week stepped up a campaign to remove Najib, who came into office in 2009 promising clean government and a more relaxed rule.

Mahathir had demanded answers over the state investment fund 1Malaysia Development Berhad (1MDB).

Fears that 1MDB could collapse have rattled the ringgit currency.

‘I recognise that there are a number of questions swirling around 1MDB. Some of these questions are valid, but there are others that appear to be directed at the company solely with the intention of creating controversy,’ Najib said.

Mahathir, 89, spearheaded a successful campaign to oust Najib's predecessor, Abdullah Ahmad Badawi, in 2009.

The retired former premier also waded into taboo territory recently by raising a past scandal linked to Najib involving the 2002 purchase of French submarines.

The deal has been clouded by allegations of kickbacks to Malaysian officials and the still-murky 2006 murder of a Mongolian woman involved in the negotiations, amid suspicions she was killed to silence her about the deal.

Two of Najib's bodyguards were convicted of the murder and have been sentenced to death.

In his interview, Najib repeated an earlier denial of any involvement in the murder, or that he knew the woman, Altantuya Shaariibuu.

Najib led the ruling coalition that has governed for 58 years to its worst election showing ever in 2013.

His government has since cracked down, arresting scores of critics on a range of charges.

The terrorism and sedition laws have been denounced by international rights groups, but Najib said Thursday both were necessary to safeguard stability.

Political analysts say Najib retains control of his ruling party and looked unlikely to be ousted for now.