Since 2015, more than 3 million Venezuelans have left the country due to the ongoing political strife.
What led to the events of Tuesday? Here’s a look at how the country got to this point.
A timeline of the events that led to the current crisis in Venezuela:
On March 5, Venezuelan President Hugo Chávez, 58, dies of cancer. Within a month, Maduro, Chávez's hand-picked replacement, is elected president by a margin of 1.6 percent. Amid claims of corruption, the National Assembly, the country's legislative body, does not recognize Maduro's presidency.
Chávez was a popular president because he nationalized the oil industry and used the profits to fund food subsidies, education and health care programs. That spending continues under Maduro until the revenue from oil reserves drops around this time, creating a deficit that begins to tank the country’s economy.
Opposition leaders Leopoldo López and María Corina Machado lead protests to begin a campaign to remove Maduro from office amid growing shortages of food and other goods and an economic recession that had begun to grow.
Lopez is charged with fomenting unrest in the protests. He will spend three years in prison before he is put under house arrest after his release from prison.
On Dec. 6, 2015, the opposition Democratic party gains a supermajority in the National Assembly.
Maduro moves to block the party’s power by stacking the country’s Supreme Court with justices loyal to him. The court blocks a handful of legislators prior to their swearing-in.
Maduro declares an "economic emergency" in January as oil prices continue to fall. He says the government cannot afford to import goods – including food.
In the spring of 2017, the Venezuelan Supreme Court bans an opposition leader from participating in elections. Protests break out across the country.
On July 30, the Constituent Assembly is created to change the country’s constitution, and the National Assembly is stripped of its power.
Maduro is reelected president May 20 in an election that is widely considered to be rigged.
The United States and the Lima Group – mostly right-leaning Latin American governments – do not recognize the results of the controversial election.
The annual inflation rate reaches 1,300,000 percent in the 12 months prior to November 2018, according to a study by National Assembly.
On Jan. 5, Guaidó is appointed as the head of the opposition National Assembly. He cites articles 233 and 333 of the Venezuelan Constitution, which says if an election is in question, the head of the National Assembly takes over as interim president.
Maduro is inaugurated Jan. 10, and Venezuelans protest. Two weeks later, Guaidó calls for Maduro to step down and claims that under the country’s constitution, he should be interim president
As the United States issues statements of support for Guaidó, Maduro cuts diplomatic ties with America.
On Jan. 28, the U.S. implements sanctions preventing Venezuelan oil company PDVSA from collecting money on crude exports to the United States. The move cuts off the main source of Venezuelan government revenue.
On Jan. 30, the Venezuelan Supreme Court imposes a travel ban on Guaidó and freezes his assets.
On Feb. 4, Germany, France, Britain and Spain announce they back Guaidó.
On Feb. 8, the U.S. sends humanitarian aid to the country amid severe shortages of food and medicine, but the aid was turned back at Venezuela's border with Colombia. Maduro also stopped aid from coming into the country via the border with Brazil on Feb. 21.
During the month, Guaidó urges high-ranking military members to join the opposition to Maduro's presidency. In an op-ed in The New York Times, Guaidó offers amnesty to anyone who opposes Maduro's government.
On Feb. 25, Guaidó meets with Vice President Mike Pence and the presidents of Colombia, Brazil, Paraguay, Argentina and Ecuador.
On Feb. 26, President Donald Trump issues an ultimatum to the Venezuelan military to side with Guaidó or be prepared to “lose everything.”
"If you choose this path, you will find no safe harbor, no easy exit and no way out," Trump said in a speech. "You will lose everything."
Also on that day, Hugo Carvajal, the country's former intelligence head, denounces Maduro.
In April, Carvajal is arrested in Spain on drug trafficking charges.
On March 5, Guaidó gets support from the unions, he tweets.
On March 11, after five days of blackouts in the country, Guaidó declares a state of emergency.
On March 16, Guaidó says he is launching a renewed campaign to oust Maduro before "reclaiming the presidential palace."
On March 21, Trump’s national security advisor, John Bolton, says the Venezuelan government has made a “big mistake” by detaining Guaidó’s chief of staff.
On March 28, Guaidó is barred from serving in the public offices in Venezuela for 15 years, according to the Maduro government.
On April 4, Guaidó gets support from the European Union as it condemns Venezuela for removing parliamentary protections that covered Guaidó.
On April 10, Pence calls for the United Nations to recognize Guaidó as the country’s leader.
On April 19, Guaidó calls for the largest march in the history of the country on May 1.
On April 30, Guaidó announces that "the moment is now" to oust Maduro. Guaidó is seen launching a military-backed operation from a military base near Caracas.
Sources: The BBC, World Vision, PBS, Reuters