By Andrew Cawthorne and Deisy Buitrago
CARACAS (Reuters) - Venezuela's opposition alliance launched a campaign on Tuesday to oust President Nicolas Maduro, vowing to hold protest rallies and push for both a recall referendum and constitutional amendment to end his presidency.
"Change is coming and no one can stop it," the head of the Democratic Unity coalition Jesus Torrealba told a news conference.
Hungry for power after 17 years of socialist rule begun by the late Hugo Chavez, Venezuela's opposition capitalized on public ire over the crisis-hit economy to win control of the National Assembly legislature in December.
Now it is counting on a multi-pronged attack against Chavez's successor to bring him down half-way through his six-year term in the South American OPEC member nation.
Reading a communique from the coalition, Torrealba said its more than two dozen parties had decided unanimously to activate "all the mechanisms for change" in Venezuela's constitution in search of a "national unity government."
Despite the show of unity, however, the coalition is notoriously fractious, with a moderate wing led by twice-presidential candidate Henrique Capriles and a more radical side headed by jailed protest leader Leopoldo Lopez.
Removing Maduro will be difficult because the government can count on friendly electoral and judicial institutions to help it frustrate opposition plans with delaying or blocking tactics.
Government figures have condemned the opposition's plans as a U.S.-backed attempt to bring about a coup d'etat in the nation of 29 million people with the world's largest oil reserves.
"They want to organize street rallies to generate violence and bring about a coup, supported by U.S. imperialism," the Socialist Party's powerful No. 2 Diosdado Cabello and former National Assembly head said this week.
RALLIES TO START AT WEEKEND
The opposition promised to begin street rallies from Saturday in Caracas.
Activists will, however, be wary of repeating the experience of 2014 when anti-Maduro protests turned violent, leading to the death of 43 people on both sides, hundreds of injuries, thousands of arrests, and widespread damage to the economy.
That push, led by opposition hardliners, did not win significant support from Venezuela's poor majority and arguably strengthened Maduro by enabling him to show a strong hand.
Two years on, however, public fury is high and small protests are breaking out daily over food and medicine shortages, power and water cuts, and transport price rises.
Masked youths faced off with police on Monday evening in the volatile western city of San Cristobal, which saw the first and most violent of the 2014 clashes.
Capriles is backing a recall referendum, as allowed under Venezuela's constitution half-way through a presidential term, and has already begun campaigning for it across the country.
Under the constitutional terms for the plebiscite, the opposition would need to collect 3.9 million signatures in three days, ratified by the national electoral board, to trigger a referendum three months later. The number who vote against Maduro would need to be more than the 7.5 million who backed him in the 2013 presidential election.
If authorities delay such a vote into 2017, then Maduro's vice-president would be allowed to complete his term, thus thwarting the opposition's desire to take power.
The other mechanism sought by the opposition coalition is a constitutional amendment to cut Maduro's term. That could be requested either by the National Assembly or 2.9 million voters, clearing the way for a referendum.
But Venezuela's Supreme Court, which has backed the government against the opposition-controlled congress in a slew of recent controversial rulings, may shoot down any attempt to reduce the current presidential term as unconstitutional.
(Additional reporting by Corina Pons in Caracas and Anggy Polanco in San Cristobal Editing by W Simon)