KUALA LUMPUR (REUTERS) - Former Malaysian strongman Mahathir Mohamad lashed out at Prime Minister Najib Razak on his blog on Tuesday, questioning his refusal to address concerns on state fund 1MDB, after calling for him to step down over the weekend.
Malaysia's longest-serving prime minister withdrew support for Najib last year after the ruling Barisan Nasional (BN) coalition lost a popular vote in the 2013 elections.
Mahathir, 89, has recently attacked Najib for problems with the economy, the debt-laden state fund 1MDB and also called for an investigation into the murder of a Mongolian model in 2006, of which two officers, part of Najib's personal security detail at the time, were found guilty.
"There are so many scandals surrounding him (Najib) now. His popularity is now even lower than when he led BN in 2013,"Mahathir said in Tuesday's post.
Mahathir questioned the excess fees paid by state property-to-energy firm 1MDB to its advisers Goldman Sachs, and the fund's level of debt.
"A prime minister must be seen to be clean and able to explain and answer questions and to be good for the country,"said Mahathir, who led Malaysia for 22 years until 2003.
"Najib cannot even answer and has not answered any question, beyond exercising elegant silence or saying the allegations are not true."
1MDB, whose advisory board is chaired by Najib, is facing criticism over its debt of nearly 42 billion ringgit (S$15.66 billion) and alleged financial mismanagement.
Najib has ordered an official enquiry into the accounts of the fund.
Mahathir said he remained loyal to the ruling United Malays National Organisation (UMNO) but disagreed with its leader, Najib.
"It is simply because I want to see the party win. It will not win if Najib is the leader," said Mahathir.
The standoff between Mahathir, who still commands influence inside UMNO, and Najib is similar to the former leader's spat with the last Prime Minister Abdullah Ahmad Badawi.
After a poor election show in 2008, Mahathir and other UMNO leaders moved against Badawi resulting in Najib becoming the next prime minister in 2009.
In a blog posting on Saturday, Mahathir openly called for Najib to step down, declaring that it was the only way the ruling UMNO can stay in power.