Brazil's suspended lower house Speaker Eduardo Cunha has been dealt a major blow after a committee voted in favour of stripping him of his seat.
Mr Cunha is widely regarded as the architect of the impeachment process of President Dilma Rousseff.
He has been accused of lying about undeclared Swiss bank accounts but strongly denies any wrongdoing.
If the full lower house approve the move, he faces losing his partial immunity from prosecution.
He could then be arrested and prosecuted on corruption charges.
The vote in the congressional ethics committee was tight, with members approving the motion 11-9 in favour.
"We are facing the biggest scandal this body has ever ruled on," said ethics council rapporteur Marcos Rogerio, who wrote the report recommending that Mr Cunha be stripped of his seat.
Mr Cunha has insisted he is innocent and vowed to appeal against the decision to another congressional committee.
Swiss authorities say Mr Cunha had secret accounts worth about $5m (£3.2m) which Brazilian prosecutors allege are linked to a corruption scheme at the state oil company, Petrobras.
Mr Cunha, a committed evangelical Christian who often quotes the Bible in his social media messages, has said that the accounts in Switzerland were trust funds that he did not control.
He was suspended last month, accused of trying to obstruct the corruption investigation against him and intimidating lawmakers.
Ms Rousseff and her supporters say it was her government's decision not to give in to Mr Cunha's demands, specifically over the ethics committee investigation, that triggered his subsequent move to begin impeachment proceedings.
Petrobras is at the centre of a massive kickbacks scandal which has led to the arrest of dozens of Brazilian lawmakers and top businessmen.
