Brazilian President Luiz Inácio Lula da Silva has accused ex-leader Jair Bolsonaro’s allies of aiding an attack on the presidential palace on Sunday.
Lula said he was convinced supporters of Mr Bolsonaro inside the palace had been complicit by allowing rioters to enter key state buildings.
And he vowed to carry out a thorough screening of palace employees in the wake of the attempted insurrection.
Some 1,500 people have already been detained in connection with the attack.
“I am convinced that the door to the Planalto palace was opened so these people could get in because I didn’t see the front door had been broken down. And that means that somebody facilitated their entry here,” Lula told reporters in the capital Brasilia.
“Many people in the military police were complicit,” the veteran leftist politician said. “There were many people in the armed forces here inside [the palace] who were complicit.”
In the wake of the attack on Sunday, Lula accused local security officials – who were commanded by Mr Bolsonaro’s former Justice Minister Anderson Torres – of incompetence or active involvement with the rioters.
And he doubled down on the allegations on Thursday, telling reporters that the presidential palace “was full of Bolsonaristas and military officials and we want to try to correct this so we can appoint career civil servants – preferably civilian ones”.
“Nobody who is suspected of being a hardcore Bolsonarista can be allowed to remain in the palace,” he went on. “How can I have someone at the door of my office who might shoot me?”
Arrest warrants have already been issued for a host of top officials, including Mr Torres, accused of being “responsible for acts and omissions” that led to the riots.
Attention has been turned to the military, widely perceived as being full of supporters of Mr Bolsonaro – a former army captain during the last military dictatorship.
The army was forced to deny reports that some of its officers had prevented police from detaining protesters, after footage showing angry exchanges between security forces emerged in local media.
But Lula has insisted Defence Minister Jose Mucio will remain in his post, telling reporters “I trust him”.
“If I had to fire a minister every time they made a mistake the turnaround would be enormous,” he added.
A member of a right-wing party, Mr Mucio was viewed as a concession to the military upon his appointment. In November, Mr Bolsonaro’s vice-president Hamilton Mourao welcomed reports of the appointment and said it would be “very well seen by the armed forces”.
Despite the mass arrest of supporters of Mr Bolsonaro, authorities have expressed concern that more rallies could be organised by his hard-line allies.
According to a memo from federal prosecutors seen by the BBC, pro-Bolsonaro groups have been calling for “mega” demonstrations to take place across Brazilian state capitals.
The government is also asking that social media platforms take steps to suspend accounts that have been involved in planning criminal behaviour.