U.S. Secretary of State Mike Pompeo says Nicolas Maduro was prepared to leave Venezuela Tuesday morning in the face of a call for an uprising by opposition leader Juan Guaido, but reversed his plan after Russia intervened.

Pompeo made the statement in an interview on CNN.

"They had an airplane on the tarmac. He was ready to leave this morning, as we understand it. Russians indicated he should stay."

Pompeo said Maduro was planning to go to Havana, but would not say whether he would have been allowed to depart safely.

There has been no comment from Russia about Pompeo's statement.

It followed Venezuelan opposition leader Juan Guaido's revived movement to seize power. He took to the streets Tuesday to call for a military uprising that drew quick support from the Trump administration but fierce resistance from forces loyal to the embattled Maduro.

Venezuela's self-proclaimed president Juan Guaido gives a thumbs up amid supporters in Altamira Plaza in Caracas Tuesday. (Fernando Llano/Associated Press)

Violent street battles erupted in parts of Caracas in what was the most serious challenge yet to Maduro's rule — kicked off with a surprise video shot at dawn of Guaido, flanked by several national guardsmen, urging a final push to topple Maduro.

"The national armed forces have taken the correct decision, and they count on the support of the Venezuelan people," Guaido said in the video, which was posted on his Twitter account.

In a surprise, Leopoldo Lopez, his political mentor and the nation's most-prominent opposition activist, stood alongside him. Detained in 2014 for leading a previous round of anti-government unrest, Lopez said he had been released from house arrest by security forces adhering to an order from Guaido.

"I want to tell the Venezuelan people: This is the moment to take to the streets and accompany these patriotic soldiers," Lopez declared. "Everyone should come to the streets, in peace."

Watch: Pro-Guaido supporters clash with pro-Maduro forces

Tensions grew through the day as pro-Guaido protesters rallied and pro-Maduro forces struck back with tear gas, rubber bullets and water cannon. 0:58

The surprise rebellion, dubbed "Operation Freedom," seemed to have garnered only limited military support, however.

"It's now or never," said one young soldier, his face covered in the blue bandanna preferred by the few dozen soldiers who stood alongside Guaido and Lopez. But by day's end, Maduro remained in power.

He appeared in a state television broadcast on Tuesday night flanked by his defence minister and socialist party vice-president, among others.

"Today the goal was a big show," Maduro said, referring to the military members who sided with Guaido as a "small group." "Their plan failed, their call failed, because Venezuela wants peace."

They … send people into the streets so that there are confrontations and deaths. And then from the blood they try to construct a narrative. - Jorge Arreaza , Maduro's foreign minister

The day had begun with the two allies, Guaido and Lopez, co-ordinating actions from vehicles parked on a highway overpass. Troops loyal to Maduro sporadically fired tear gas from inside the adjacent Carlota air base.

Venezuela's Foreign Minister Jorge Arreaza alleged that the U.S. likely paid a guard to allow Lopez escape house arrest.

"Since 2002, we've seen the same pattern," Arreaza told The Associated Press, adding that most of Caracas was calm. "They call for violence, a coup, and send people into the streets so that there are confrontations and deaths. And then from the blood they try to construct a narrative."

A crowd that quickly swelled to a few thousand scurried for cover, reappearing later with Guaido at a nearby plaza away from the disturbances.

A Venezuelan National Guard member gestures after joining anti-government protesters in a march, showing his support for opposition leader Juan Guaido in Caracas on Tuesday. (Manaure Quintero/Reuters)

A smaller group of masked youths stayed behind on the highway, lobbing rocks and Molotov cocktails toward the air base, and setting a government bus on fire.

Amid the mayhem, an armoured utility vehicle drove at full speed into the crowd. Two demonstrators, their heads and legs bloodied, were rushed away on a motorcycle.

The head of a medical centre near the site of the street battles said doctors were treating 50 people, about half of them with injuries suffered from rubber bullets. At least one person had been shot with live ammunition. Venezuelan human rights group Provea said a 24-year-old man was shot and killed during an anti-government protest in the city of La Victoria.

A screengrab taken from video shows a Venezuelan military vehicle heading into protesters in Caracas on Tuesday. It was not immediately clear if anyone was injured in the incident. (Reuters)

Maduro took to Twitter to say that the top commanders of the various divisions of the military had assured him of their loyalty.

"Nerves of steel!" he posted.

Chile's foreign minister tweeted later in the day that Lopez and his family had been admitted to a Chilean diplomatic residence in Caracas. He said they moved to Spain's embassy in Caracas Tuesday evening.

A Nicolas Maduro supporter holds a sign indicating 'hands off' as pro-Guaido supporters, separated by members of the uniformed Secret Service, rally outside of the Venezuelan Embassy in Washington Tuesday. (Andrew Harnik/Associated Press)

Flanked by top military commanders, Defence Minister Vladimir Padrino Lopez condemned Guaido's move as a "terrorist" act and "coup attempt" that was bound to fail like past uprisings.

"Those who try to take Miraflores with violence will be met with violence," he said on national television, referring to the presidential palace where hundreds of government supporters, some of them brandishing firearms, had gathered in response to a call to defend Maduro.

'Movement headed by Venezuelans'

Guaido's ambassador in the U.S., Carlos Vecchio, denied the claim that the U.S. played in role in Tuesday's development.

A military member throws a tear gas canister near the Generalisimo Francisco de Miranda Airbase in Caracas. Representatives of the Maduro government downplayed any threat early Tuesday. (Carlos Garcia Rawlins/Reuters)

Vecchio said in a news conference in Washington that the protest "is a movement headed by Venezuelans."

U.S. national security adviser John Bolton said later that what's happening "is clearly not a coup," because the U.S. and many other countries recognize opposition leader Juan Guaido as Venezuela's legitimate president. He added that U.S. President Donald Trump was monitoring developments "minute by minute" and wants a peaceful transfer of power.

Trump tweeted his support.

I am monitoring the situation in Venezuela very closely. The United States stands with the People of Venezuela and their Freedom! —@realDonaldTrump

Guaido, of Venezuela's opposition-controlled National Assembly, invoked the constitution to assume an interim presidency in January, arguing Maduro's re-election in 2018 was illegitimate.

He has been travelling outside the capital, Caracas, more and more in recent weeks to try to put pressure on Maduro to step down.

Maduro calls Guaido a U.S-backed puppet who seeks to oust him in a coup. The government has arrested his top aide, stripped Guaido of his parliamentary immunity and opened multiple probes. It has also barred him from leaving the country, a ban Guaido openly violated earlier this year.

The developments on Tuesday were being monitored closely by the international community.

Canada's Foreign Affairs Minister Chrystia Freeland tweeted: "The safety and security of [Juan Guaido] and [Leopoldo Lopez] must be guaranteed." She also called for the safety of Guaido's supporters.

Later, she reiterated Canada's support of Guaido.

Watch: Foreign Affairs Minister Chrystia Freeland says Canada commends the courage of Venezuelans in the streets:

Foreign Affairs Minister Chrystia Freeland calls on the Maduro regime to step aside now. 0:29

Freeland also said Canada would convene an emergency meeting via conference call of the Lima Group Tuesday afternoon.

The group later issued a statement — signed by Argentina, Brazil, Canada, Chile, Colombia, Costa Rica, Guatemala, Honduras, Panama, Paraguay and Peru — calling on Venezuela's military to place its loyalties with Guaido. It urged the armed forces "to cease being instruments of the illegitimate regime for the oppression of the Venezuelan people."

Mexico, which is part of the Lima Group, did not sign on. It is among a minority of Latin American countries that do not recognize Guaido as interim leader of Venezuela.

Venezuelan opposition leader Leopoldo Lopez, centre, in grey, stands near the Generalisimo Francisco de Miranda Airbase in Caracas on Tuesday. Lopez has been jailed or put in house detention for much of the past five years. (Carlos Garcia Rawlins/Reuters)

Brazil's vice-president said the situation in Venezuela has reached a point of no return.

Former Gen. Hamilton Mourao said Tuesday that either opposition leaders Guaido and Lopez would "be prisoners" or Maduro "would be leaving," adding, "There is no other way out of this."

Venezuela's ambassador to the UN, Samuel Moncada, downplayed the entire incident, saying the country was in "total normality."

"This new attempt by foreign powers to spark a civil war, open the doors to a military intervention from abroad and impose a puppet government in our country failed," he said from the UN.

March planned for Wednesday

Mexican President Andres Manuel Lopez Obrador and his foreign relations department expressed concern over a possible escalation of violence and bloodshed, with Lopez Obrador repeating in a Tuesday morning news conference that dialogue was the preferred path.

The Russian government said only that President Vladimir Putin discussed the Venezuelan situation with his top security body.

Venezuelan military deserters of the national guard are seen at the Simon Bolivar International border bridge between Colombia and Venezuela, on the outskirts of Cucuta, Colombia on Monday. (Juan Pablo Bayona/Reuters)

While Russia's foreign ministry echoed the calls of other countries to "avoid unrest and bloodshed," its statement also called on "the radical opposition" in Venezuela to stand down. Russia has provided economic and logistical support to Maduro's regime.

Guaido said soldiers who had taken to the streets were protecting Venezuela's constitution. He made the comments a day before a planned anti-government rally that he has promoted as "the largest march in Venezuela's history."

"The moment is now," he said.