By Andrew Cawthorne

CARACAS, July 22 (Reuters) - Venezuelan soldiers on motorbikes fired teargas at hundreds of masked and stone-throwing youths in Caracas on Saturday during the latest protest against President Nicolas Maduro.

The Democratic Unity coalition had called a march on the pro-Maduro Supreme Court in support of alternative magistrates appointed by the opposition on Friday. But security forces blocked their way with armored cars and riot shields.

Clashes ensued, injuring several people including student protester Wuilly Arteaga, who has become famous for playing his violin in front of security lines.

Paramedics attended Arteaga in the street as blood poured down his face, witnesses said.

"Repression is the only way this regime keeps itself in power," opposition lawmaker Luis Florido said at the march, blaming the Maduro government for the latest violence.

The opposition coalition and a self-styled youth-led "Resistance" movement launched protests in early April against Maduro whom they accuse of turning Venezuela into a dictatorship and wrecking what should be a prosperous economy.

He says demonstrators are seeking a coup with U.S. support.

Since April, more than 100 people have died in the unrest, with thousands injured and hundreds arrested. Five people died during an opposition-led national strike on Thursday.

Venezuela's long-running political crisis has entered a dangerous new stage as the opposition escalates street tactics to try and block a controversial new super-congress Maduro wants to set up via an election next weekend.

The opposition is boycotting that vote which they say is a sham intended to guarantee a majority for the unpopular Maduro. They are demanding instead conventional elections to try and end nearly two decades of Socialist Party rule.

Foes of Maduro are threatening to shut down Venezuela with protests to block the July 30 vote for the Constituent Assembly, which could re-write the constitution and disband the existing opposition-led legislature.

Foreign pressure has grown too on Maduro to abort the vote, including a threat from U.S. President Donald Trump to apply economic sanctions, potentially at the OPEC nation's oil sector which accounts for 95 percent of export revenue.

But the government is showing no sign of backing down, announcing that it will put 232,000 soldiers on the streets to ensure the Constituent Assembly goes ahead in a week's time. (Additional reporting by Carlos Garcia Rawlins, Efrain Otero, Andres Martinez Casares; Writing by Andrew Cawthorne; Editing by Chris Reese)

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