Two of Malaysia's main opposition parties on Sunday demanded an emergency sitting of parliament to discuss Prime Minister Najib Razak's future as tensions mounted over a report that linked him to probes into alleged corruption involving state fund 1MDB.
A Wall Street Journal (WSJ) report published on Friday said that investigators had traced nearly $700 million to bank accounts they believed belonged to the prime minister.
Reuters could not independently verify the report.
Najib denied taking any money from the debt-laden state fund or any other entity for personal gain.
However, the pressure was back on him on Saturday after the country's attorney-general said he had received documents from a task force investigating 1MDB that were "connected to allegations" that money was transferred into Najib's account.
"With the attorney-general's confirmation, the WSJ allegation against Najib has assumed an even more serious character and import, sparking a political and government crisis of the first magnitude never seen in Malaysia's 58-year history," Lim Kit Siang, the opposition Democratic Action Party's (DAP) parliamentary leader, said in a statement.
Members of Najib's party, the United Malays National Organisation (UMNO), have closed ranks behind the prime minister, who had already been on a back foot over the mismanagement of 1MDB and his handling of the economy.
However, the DAP and opposition People's Justice Party (PKR) sought to stoke the furore, urging the speaker of parliament's lower house to call an emergency sitting on Tuesday.
DAP lawmaker Charles Santiago said he and 72 others, including representatives of political parties and non-governmental organisations, had also lodged a police report.
"We have asked that the police investigate the WSJ's assertion that billions were deposited in Najib's personal account and take necessary actions," he told Reuters.
'Tarnishing the country's image'
1MDB, whose advisory board is chaired by Najib, has debt of nearly $11.6 billion. Even before the WSJ report it was the subject of separate investigations by the central bank, auditor general, police and the parliament's Public Accounts Committee.
Attorney-General Abdul Gani Patail said on Saturday that a task force made up of members of the anti-corruption commission, police and central bank had raided offices of three companies linked to the state investor.
The Wall Street Journal, citing documents from a government probe, said there were five deposits into Najib's account.
It said the two largest transactions, worth $620 million and $61 million, were made in 2013 from a company registered in the British Virgin Islands via a Swiss bank.
1MDB has described the allegations as "unsubstantiated", saying it never provided funds to the prime minister.
Najib has accused former premier Mahathir Mohamad, an ally-turned-critic, of fanning allegations he described as a lie.
Najib, himself the son of a prime minister and now in his second term, retains support within the long-ruling Barisan Nasional coalition.
His home (interior) minister, Ahmad Zahid Hamidi, said on Sunday that those behind the allegations appeared to be trying to undermine confidence in Malaysia's economy and government, and their actions could be "a threat to national security", the Bernama state news agency reported
"The home ministry will take action against any media that publish inaccurate information from unknown sources for the purpose of tarnishing the country's and government's image," his ministry said in a statement late on Saturday.