The president of Venezuela's National Assembly, Juan Guaidó, took an oath as interim president on Wednesday, amid nationwide marches in opposition to President Nicolás Maduro.

The United States in an official statement on Wednesday recognized Guaidó as interim president of Venezuela.

Maduro was sworn in for a second six-year term earlier this month, but his election was declared illegitimate by most of the international community, including the United States, the European Union and the Organization of American States.

ADVERTISEMENT

Guaidó, as head of the opposition-led National Assembly, has been internationally recognized as the only democratically elected leader with a claim to Venezuela's presidency.

"In my condition as president of the National Assembly, invoking the articles of the Constitution of the Bolivarian Republic of Venezuela ... I swear to assume formally the competencies of the national executive," Guaidó told a crowd of protesters in Caracas.

"In its role as the only legitimate branch of government duly elected by the Venezuelan people, the National Assembly invoked the country’s constitution to declare Nicolas Maduro illegitimate, and the office of the presidency therefore vacant. The people of Venezuela have courageously spoken out against Maduro and his regime and demanded freedom and the rule of law," President Trump Donald John TrumpObama calls on Senate not to fill Ginsburg's vacancy until after election Planned Parenthood: 'The fate of our rights' depends on Ginsburg replacement Progressive group to spend M in ad campaign on Supreme Court vacancy MORE said in the statement.

In response, Maduro broke off relations with the United States and gave U.S. diplomats 72 hours to leave the country.

"We encourage other Western Hemisphere governments to recognize National Assembly President Guaido as the Interim President of Venezuela, and we will work constructively with them in support of his efforts to restore constitutional legitimacy," Trump added.

U.S. recognition of Guaido's claim was followed by Canada, the OAS, and a slew of Latin American countries including Brazil, Argentina, Chile and Colombia.

But Mexico and Spain, key actors in the Spanish-speaking world, withheld their support.

A senior administration official said the United States expects international actors who didn't recognize Maduro's reelection to side with Guaido.

"Consequently, the next act would be to recognize Juan Guaido as the legitimate president of Venezuela," said the official.

International support notwithstanding, Guaido's claim is mostly rhetorical unless Maduro chooses to loosen his grip on power.

"The next 48 hours are about whether they jail Guaido, whether he ends up in an embassy, whether he is already in the States, and what Maduro does to the U.S. embassy in Caracas," said Michael McCarthy, an expert on Venezuela at American University.

Trump administration officials said U.S. support of Guaido includes transferring sovereign power over international transactions to his interim government -- essentially giving him control over Venezuela's foreign assets.

But it's unclear whether the U.S. government has the power to do so immediately.

"Venezuela's lawyers will try to stop this. It's going to be pretty contested," said McCarthy.

"How they actually seize the assets -- there's still a U.S. court system, foreign immunity. There are major hurdles before you can deposit the cash," he added.

Still, the United States is vowing to increase pressure on Maduro while supporting Guaido.

The Trump administration has steadily increased sanctions on individuals and entities linked to the Maduro regime, including widespread sanctions on the gold trade, a major source of foreign currency for Venezuela.

Administration officials said further economic and diplomatic actions are on the table.

"Everything is on the table, all options, but on the economic sphere, if you look at what we've done, there is still a tremendous amount of leverage in our toolbox," said the senior official.

"In our sanctions we've barely scratched the surface on what actions the United States can take on an economic sanctions front," he added.

Administration officials have not publicly discussed military action against Venezuela, but warned against violent repercussions against Guaido and the National Assembly.

"We have a host of options, we will take every single one of those options seriously," said the administration official.

"[The Maduro regime has] no immediate future, they will have no immediate livelihood, and they will have their days counted," he added.

Still, the U.S. is looking for more international allies to join Guaido's camp and will seek to provoke a reaction that further mines Maduro's legitimacy, said McCarthy.

"The White House and others are still interested in continuing to prove to the world how authoritarian the government is, so it's a process of baiting them to make these mistakes," said McCarthy.

"The next step is going to be a bunch of tit-for-tat stuff, and how far it goes is the question," he added.

Updated at 3:55 p.m.