The National Electoral Council in Venezuela has declared invalid a petition signed by more than three million people demanding a referendum on the rule of President Hugo Chavez.
Thousands of Chavez supporters staged a protest near the council
The Council's president said the petition had been rejected because the signatures were gathered months before the mid-point of Mr Chavez's term in office.
Under the Venezuelan constitution, a president may be challenged after serving half of the six-year term.
But the president - who commands strong support among the country's poor - says a political elite is pushing for his removal to regain the privileges it lost when he took power.
The Council did not examine the signatures themselves, but said opposition leaders failed to meet several
technical requirements - from waiting until the half-way point in Mr Chavez's term on 19 August to addressing the petition directly to the council.
Before the electoral body announced its decision, several thousand Chavez supporters carrying banners staged a protest near the council in Caracas protected by National Guard troops in riot gear.
On Wednesday, opposition leaders said they would organise a new collection of signatures if the authorities failed to recognise the first one.
They said they would do it as many times as was necessary to end Mr Chavez's presidency and have asked for clarification of the rules.
Opposition groups delivered the petition - signed by more than three million people - to the electoral authorities.
Venezuela's Constitution says citizens need
signatures from 20% of the electorate (2.4 million
people) to demand the vote.
But the constitution is unclear about many details, including when the signature gathering process can
President Chavez, who was elected on promises to bring about economic prosperity in the world's fifth largest oil exporter country, has been accused of mismanaging the economy.
The recall is the third attempt by Chavez opponents to oust him, after a failed coup in 2002 and a general strike
this year which crippled the country's crude exports.