Anti-government activists listen to the president of Venezuela's opposition-led National Assembly Juan Guaido in Caracas on January 11, 2019
Caracas (AFP) - Venezuela's sidelined opposition-controlled legislature is calling for a mass protest against President Nicolas Maduro in a bid to oust the socialist leader in favor of "a transitional government."
Maduro, 56, was sworn in for a second term on Thursday, having won a controversial election in May that was boycotted by the opposition and branded a fraud by the United States, European Union and Organization of American States.
The president of the National Assembly, Juan Guaido, said Friday that the constitution gives the legislature the right to assume transitional power after declaring Maduro a "usurper," but said it would need military backing and for people to take to the streets to demand change.
"Is it enough to lean on the constitution in a dictatorship? No. It needs to be the people, the military and the international community that lead us to take over," said the 35 year-old Guaido, speaking to a crowd of around 1,000 opposition supporters in Caracas.
In response, prisons minister Iris Varela threatened Guaido on Twitter, saying she had a cell ready for him -- as Maduro dismissed the opposition as "little boys."
"I hope you quickly name your cabinet to know who is going to accompany you," Varela said.
- Foreign support for Guaido -
But Guaido's announcement was welcomed outside of Venezuela.
US National Security Advisor John Bolton said the administration of President Donald Trump "resolutely supports the Venezuelan National Assembly, the only legitimate branch of government duly elected by the Venezuelan people," and especially supports "the courageous decision" by Guaido to "declare that Maduro does not legitimately hold the country's presidency."
In Washington, OAS Secretary General Luis Almagro recognized Guaido as head of state, as the person at the top of Venezuela's only legitimate governing body.
"We welcome the assumption of @jguaido as interim President of Venezuela," Almagro tweeted.
Brazil's far-right government welcomed Guaido's readiness to "constitutionally assume the Venezuelan presidency."
Guaido called for a mass protest on January 23 -- the day in 1958 on which the military dictatorship of Marcos Perez Jimenez fell.
The National Assembly has dismissed Maduro's election as illegitimate, but the body has been sidelined by the president's power grab.
Having lost control of the legislature in 2016, Maduro last year created a rival Constituent Assembly filled with loyalists.
And all decisions taken by the National Assembly are considered null and void by Venezuela's Supreme Court, the pro-government Supreme Justice Tribunal.
Maduro's swearing in ceremony was even held at the Supreme Justice Tribunal.
The hand-picked successor to late strongman Hugo Chavez also has the backing of the military high command, which reiterated its "loyalty" to the president on both Wednesday and Thursday.
But as part of his call for the military to sever ties with Maduro, Guaido announced that the legislature would pass an amnesty law for military members imprisoned on conspiracy charges.
Mass protests demanding Maduro's exit also erupted in 2014 and 2017, leaving around 200 dead and hundreds arrested.
Maduro is widely blamed for the country's economic crisis, with basic food and medicine scarce and hyperinflation estimated to reach 10 million percent in 2019, according to the IMF.