Salud Chacao director Maggia Santi said Tuesday that 30 of those injured were shot with rubber bullets. Another 16 sustained bodily trauma, three reported difficulty breathing and one was shot with a firearm.
She said doctors have sufficient supplies to treat the injured, in part due to recent donations by organisations including the Red Cross.
At least 11 people were detained, according to a local organisation that tracks political prisoners.
The day began with a dawn video address by Guaidó, in which he was surrounded by armed men in military uniforms and urged other troops to join the final stage of «Operation Liberty» to force Maduro from power.
«People of Venezuela, the end of usurpation has arrived,» Guaido said. «At this moment, I am with the main military units of our armed forces, starting the final phase of Operation Liberty. People of Venezuela, we will go to the street with the armed forces to continue taking the streets until we consolidate the end of usurpation, which is already irreversible.»
Maduro’s communication’s minister tweeted that the government was moving to confront a «coup» and was attempting to «deactivate» what he described as a «reduced group of military officials who are traitors» and who had positioned themselves in the Altamira district of the capital.
Outside the La Carlota military base in the eastern district of Altamira, people started to join Guaido’s call to protest and were met by tear gas canisters. It was not immediately clear who fired the tear gas.
Maduro’s defence minister, Vladimir Padrino Lopez, insisted in a separate tweet that the majority of the military remains loyal to the government.
«The Bolivarian Armed Forces stand firm in defense of the national constitution and its legitimate authorities,» he tweeted. He added: «We reject this coup-like movement that seeks to fill the country with violence. The pseudo political leaders that are heading the subversive movement have employed troops and police with war weapons in a street of the city to create terror.»
In a live phone interview on state-run television, chief prosecutor Tarek William Saab said: «Our position is to defend democracy. We will not hesitate to act, without violating the constitution, against the ones who have led an embarrassing show … We will act, with all calm, at the right moment.»
Diosdado Cabello, a leading pro-Maduro politician, called on government supporters to gather at the Miraflores presidential palace to defend Maduro. «We will be absolutely inflexible, radical in the defense of the Bolivarian revolution,» he vowed on state TV. «That’s why we are mobilised.»
National Security Advisor John Bolton tweeted US support of Guaido’s National Assembly.
«The [Venezuelan military] must protect the Constitution and the Venezuelan people,» he wrote «It should stand by the National Assembly and the legitimate institutions against the usurpation of democracy. The United States stands with the people of Venezuela.»
NetBlocks, an organisation that tracks connection and electricity services in Venezuela, said on Twitter that «multiple internet services» are currently being «restricted.»
Guaido called for «nonviolent» action, but the video had the hallmarks of perhaps the most significant military challenge to Maduro’s power since Guaido – the head of the opposition-controlled National Assembly – invoked constitutional powers, called Maduro a usurper and claimed the true mantle of leadership as Venezuela’s interim president.
His claim has since been recognised by nearly 60 nations, including the United States, which is vigorously backing him and has called on Venezuela’s military to reject Maduro.
On Tuesday – a day before a planned opposition protest – Guaido stood in front of Leopoldo Lopez, his political mentor and a longtime opposition figure who has been ordered under house arrest. His presence signified a defiant breaking of that order.
«Venezuela: the final phase for the end of usurpation has arrived, Operation Freedom,» Lopez tweeted. «I have been freed by military men of the constitution, and of President Guaido. I’m at the La Carlota Base. We have to mobilise. It’s time to conquer freedom. Strength and Faith»
The early-morning events set the stage for a potentially dramatic confrontation between Maduro’s government and Guaido’s backers.
«The assassin ultra-right joined this attempt, announcing its violent agenda months ago,» Jorge Rodriguez, Maduro’s communication minister, tweeted. «We call the people to stay in maximum alert with the glorious Bolivarian armed forces to overcome this coup attempt and preserve the peace.»
US Senator Marco Rubio, who has strongly backed Guaido, issued a call for the military to rise up: «This is the moment for those military officers in #Venezuela to fulfil their constitutional oath & defend the legitimate interim President @jguaido, in this effort to restore democracy,» he tweeted. «You can write history in the hours & days ahead.»
The Washington Post, AP