(Adds confirmation of lawyer's arrest)
By Andrew Cawthorne
CARACAS, July 22 (Reuters) - Venezuela's opposition called a two-day national strike against President Nicolas Maduro after another day of violent clashes on Saturday where the injured included a violinist famous for his musical protests.
The opposition coalition - which organized a 24-hour shutdown this week that was heeded by millions and paralyzed large swathes of the South American nation - said the next strike would be on Wednesday and Thursday.
Mass marches were also planned for Monday and Friday in an effort to force Maduro into aborting a controversial July 30 election for a new congress.
The fast-escalating political showdown in the South American OPEC nation comes after more than 100 people have died and thousands more been injured in anti-government unrest since demonstrations began in April.
"The Venezuelan people are not giving up, they are valiant, they will come out to defend democracy and the constitution," opposition lawmaker Simon Calzadilla said at a news conference flanked by other coalition officials.
Foes accuse Maduro of turning Venezuela into a dictatorship and wrecking what should be a prosperous economy. They want free elections and an end to two decades of socialist rule.
Maduro, 54, calls himself a flag bearer for the international left, up against right-wing "terrorists" seeking a coup with the connivance of the United States and foreign media.
BLOODIED MUSICIAN
On Saturday, several thousand protesters sought to march on the pro-Maduro Supreme Court in support of alternative magistrates appointed by the opposition. But security forces blocked them with armored cars and riot shields.
Clashes ensued for several hours as hundreds of masked youths hurled stones and Molotov cocktails at National Guard troops firing tear gas from motorcycles.
The injured included musician Wuilly Arteaga. The 23-year-old has become famous for playing the national anthem on his violin in front of security lines as battles rage around him.
Paramedics attended Arteaga in the street as blood poured down his face. He later tweeted a video from hospital with a bandaged face and clutching his violin.
"Neither rubber bullets nor pellets will stop our fight," said Arteaga. "Tomorrow I will be back in the streets."
The opposition is stepping up street tactics in what it dubs "hour zero" for Venezuela to try and block the new Constituent Assembly that Maduro wants to create next weekend. The opposition is boycotting that vote, calling it a sham and demanding conventional elections instead.