Five things to know about Venezuela's escalating political crisis:

HOW DID THE UNREST BEGIN?

In late March, the government-stacked Supreme Court issued a ruling stripping the opposition-controlled National Assembly of its last powers. The decision was later reversed amid a widespread international criticism, but it launched near protests in which at least 75 people have died.

Opposition leaders gained a majority in the National Assembly's 2015 legislative election amid mounting frustration over President Nicolas Maduro's handling of the economy, spiraling crime and food shortages. The Supreme Court nullified eight of the assembly's laws between January and October 2016, after making just one such ruling in the previous 200 years, legal experts say.

Protesters contend Maduro's government has become authoritarian and are vowing to escalate their opposition leading up to a July 30th election called by Maduro to convene a special assembly that will rewrite the nation's constitution.

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WILL THE MILITARY INTERVENE?

The military has historically been an arbiter of political disputes in Venezuela and the opposition is calling on it to uphold the constitution and stop Maduro from further consolidating his power.

But so far there is little to suggest a mass revolt is underway and popular support for the military is at an all-time low.

Late President Hugo Chavez and Maduro have spent years winning over top military brass with bonuses in sought-after dollars, powerful government jobs and patronage. Only a handful of officers have publicly expressed any disgruntlement.

Tuesday's helicopter attack is believed to have been carried out by Oscar Perez, an apparent police pilot and budding action movie actor. He called for a rebellion against Maduro's government but there was no sign that more than a handful of other police or troops were taking part.

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CHOPPER ATTACK

Maduro's government says the pilot fired 15 shots at the Interior Ministry and four grenades at the Supreme Court in what they characterize as a "terrorist attack."

Video circulating on social media shows the helicopter circling the court followed by the sound of several loud explosions.

There were no injuries in the attack and no visible signs of damage outside either government building Wednesday.

Opposition leaders are questioning the government's version of events and say it may be an attempt to distract attention from Maduro's controversial push to rewrite the constitution.

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DEATHS AND LOOTING MOUNT

The number of people killed in protests and looting is approaching nearly twice that seen in 2014, in which more than 40 Venezuelans were killed.

Opposition leaders point to armed, pro-government groups known as "colectivos" for the deaths, while the government contends youth paid by the opposition are responsible for the violence. Most of those killed have been young men aligned with the opposition.

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WHAT'S AT STAKE?

If Maduro proceeds with his plans to rewrite the constitution, Venezuela's government could soon look dramatically different.

While the National Electoral Council has called for delayed regional elections to be held in December, the special assembly could cancel them and 2018 presidential elections.

Venezuela's economy is forecast to shrink by 8 per cent this year and inflation could soar to four digits. Polls indicate at least 75 per cent of Venezuelans want Maduro gone but many do not have a favourable opinion of the opposition either.

Maduro warned earlier this week he is willing to do whatever it takes to defend Chavez's revolution, even if it means using arms.