Those supporting the National Assembly leader took to the streets calling for the fall of Maduro. Military forces loyal to President Maduro have responded at times with violence.
One demonstrator, Victor Zabala, 25, told The Guardian he was struck multiple times by rubber bullets. He accused the National Guard of also using live fire on groups of protesters.
In one video, military vehicles appeared to mow down Guaido supporters, who responded by throwing objects.
CNN and BBC reported a number of cable companies in Venezuela received orders to stop airing the networks after they aired the graphic footage.
Venezuelan media reported at least 69 people were hospitalized with injuries Tuesday, including two with gunshot wounds.
Guaido called for non-violent protests to support what he called "Operation Liberty." He made the announcement in a video in which he is flanked by Venezuelan military forces.
"People of Venezuela, the end of usurpation has arrived," Guaido said in the video, taken at the La Carlota air base.
"At this moment, I am with main military units of our armed forces, starting the final phase of Operation Liberty. People of Venezuela, we will go to the streets with the armed forces to continue taking the streets until we consolidate the end of usurpation, which is already irreversible," he continued, calling for nationwide demonstrations for Wednesday.
Chilean officials said Lopez and his family sought safety at the Chilean Embassy in Caracas before moving to the Spanish Embassy.
Maduro's administration said Guaido's move is a coup attempt and called the military members who've sided with Guaido "traitors."
"The Bolivarian Armed Forces stand firm in defense of the national constitution and its legitimate authorities," Venezuela defense minister Vladimir Padrino Lopez said.
"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," he added.
Between 500 and 600 Maduro supporters gathered outside the presidential palace.
While many foreign governments have backed Guaido as Venezuela's "interim" president, Bolivian President Evo Morales voiced opposition and blamed the United States, which also recognizes Guaido as Venezuela's leader.
"The U.S., with its meddling and coup-waging, looks to wreak violence and death in Venezuela, caring only about its interests and nothing about the human loses," Morales said. "We must be united on our guard so that the coup-perpetrators never return to our region."
U.S. national security adviser John Bolton called for a peaceful transfer of power and said it was "a very serious situation."
"This is clearly not a coup," he added because the United States views Guaido as the leader of Venezuela.
Meanwhile, President Donald Trump accused Cuba of aiding the Maduro government and threatened to punish the island nation with heavy sanctions and an embargo.
"If Cuban troops and militia do not immediately cease military and other operations for the purpose of causing death and destruction to the Constitution of Venezuela, a full and complete embargo, together with highest-level sanctions will be placed on the island of Cuba," he said in a tweet. "Hopefully, all Cuban soldiers will promptly and peacefully return to their island!"