Romania's constitutional court has approved the appointment of an interim president, following a vote by MPs to suspend President Traian Basescu.
Thousands of supporters have rallied for Mr Basescu (centre)
The court ruled that parliament - controlled by Mr Basescu's opponents - had the right to oust him on Thursday.
The leftist Speaker of the Senate (the upper chamber), Nicolae Vacaroiu, will replace him temporarily.
The development clears the way for parliament to organise a referendum on Mr Basescu's impeachment.
He has been accused of abusing his office by overriding the cabinet and criticising the judiciary - charges he says are politically motivated.
Correspondents say any move to impeach Mr Basescu is likely to fail because he remains the most popular politician in the country.
Earlier, the European Commission voiced concern that the current political crisis in Romania could weaken the fight against corruption and commitment to judicial reform in the country.
Mr Basescu has been at odds for several months with the Prime Minister, Calin Popescu Tariceanu. They have accused each other on television of involvement in dubious multi-million-dollar energy deals.
In the parliament on Thursday, 322 members voted to suspend Mr Basescu, with 108 against and 10 abstentions.
The suspension was proposed by the leftist opposition party PSD.
Mr Basescu denies any wrongdoing and has vowed to resign if a referendum on his impeachment is called.
But the BBC's Nick Thorpe in the region says he is expected to resign on Monday.