
"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.