Venezuela's President Nicolas Maduro is facing one of the most severe challenges to his authority since assuming power in 2013.

Opposition leader Juan Guaido, backed by the United States, declared himself the country's interim president, calling Maduro's second term as president illegitimate.

A defiant Maduro responded, announcing he was severing diplomatic and political relations with the US, and ordering American diplomats to leave the country within 72 hours. Russia, China and Turkey came to Maduro's defence, denouncing US interference in Venezuela.

"We are defending the right to the very existence of our Bolivarian Republic," Maduro said. "They intend to govern Venezuela from Washington. Do you want a puppet government controlled by Washington?"

Analysts say the latest developments are not a surprise, with many saying it's part of an agenda built by the US. Yet they also say that as uncertainty ripples, the coming days will be a crucial test for Maduro, the opposition and the country's future.

"The US support to Guaido could have serious implications for Maduro's rule," Carlos Eduardo Pina, a Venezuelan political scientist, said.

"The American administration could take the decision of not allowing the government to manage their dollar accounts and they could end up losing control of the international accounts from [the] state-run oil company Petroleos de Venezuela (PDVSA)," he explained.

190123205835912

Last year, Venezuela exported about 500,000 barrels of crude oil a day to the US, according to the US Energy Department as cited by Reuters news agency. Oil revenues account for about 98 percent of export earnings, and although the US is not Venezuela's only client, it is one of the most important.

"Nicolas Maduro controls most of the institutions and the military forces, however, if he loses control of the income that the oil industry generates, if this instead reaches to Guaido, as the recognised president, that will be a major blow for [Maduro's] government," Pina added.

Struggle for the military's lower ranks

But Guaido will also struggle to take control of the country without the backing of the military, which disavowed his claim to power and threw its support behind Maduro.

On Thursday, Defence Minister Vladimir Padrino Lopez accused Guaido of staging a coup and said Maduro is the "legitimate president".

190124102403407

"It's one thing to self-proclaim yourself president, another thing is to be able to exercise that power," political analyst Marco Terugi told Al Jazeera.

"The power is only relevant when you can execute it, and the power is still with the president and the military forces," he added.

Maduro has ordered Guaido's arrest.

Although the military's top brass indicated their support for Maduro, analysts say Guaido will continue to seek to try to win over those of the lower ranks.

"The lower ranks are not satisfied with what is taking place," Pina said.

"In 2018, there were small uprisings from that sector that were not reported, there is discomfort among them, as they also face the critical conditions people are facing," he added.

Pina said it is likely that the opposition-controlled National Assembly will pass legislation giving amnesty for those in the military.

"The opposition managed to move to the streets, control the National Assembly, but it's lacking the military support," Pina said. "That is the last step needed to accomplish its political agenda."

More sanctions expected

On Thursday, all eyes will also be on Guaido as he sets his agenda for what comes next and on Washington, DC, where members of the Organization of American States (OAS) are set to meet on the crisis.

190124033139731

Analysts also expect more unrest, and more US sanctions may follow.

"In the next days we will witness huge tension between both forces; the opposition will try to execute a coup and the road proposed can only be accomplished with violence," Terugi said.

According to Venezuelan watchdog groups, at least 12 people have been killed since the recent unrest began earlier this week.

"More sanctions are expected, and this will severely impact people" he added.

"But all of this will end up unifying the Chavismo even further, and they won't manage to break the alliance between the armed forces and the administration."

Government supporter Juan Romero echoed that sentiment, saying the opposition "has no legitimacy".

"Venezuelans are ready to defend the country from these internal and external forces that seek to destabilise the country and force a political transition," said Romero, who is also the deputy of the Legislative Council of the State of Zulia.

'Now or never'

For Guaido's part, analysts believe he has re-energised the divided opposition, but his next steps will show if he's able to retain that support.

190124062525471

"I'm surprised by the support Guaido has gathered," said Ronal Rodriguez, a political science professor at Rosario University in Colombia.

"The opposition was divided, and now it's reconnecting again," he told Al Jazeera. "Many believe that it's now or never, if they don't manage to trigger a change now, they fear for what might come next."

Rodriguez added that if Guaido is able to force a transition of power, his government will have to "play its cards wisely".

"They can't exclude or suffocate the Chavismo, that will be a mistake and that will eventually lead to subversion," he said.