Emboldened by opposition leader Juan Guaido's attempts to force in humanitarian aid through the borders with Colombia and Brazil, hundreds of military personnel took the chance to flee a country wracked by poverty and recession.

Some 326 members of the military and police crossed into Colombia with another seven heading to Brazil to get away from the chronic shortages of food and medicine that have made daily life a struggle for millions.

That may sound like a small number among the 365,000 members of the armed forces and almost two million civilian militia, but analyst Luis Salamanca says a drip can quickly turn into a flood.

"Maduro's military power is subject to that same erosive dynamic that his popular support suffered from," Salamanca told AFP.

"The desertions are part of a process of attrition, an undermining of the foundations."

The military is Maduro's most potent backer, which is why Guaido, recognized as Venezuela's interim president by 50 countries, is so keen to turn their heads.

He's even offered an amnesty to anyone turning their back on Maduro.

Although Guaido's efforts to bring in humanitarian aid, as he'd promised to do on Saturday, floundered against a blockade by a determined military that remains loyal to Maduro, he did score some smaller victories.

The initial trickle of defecting soldiers has increased exponentially, while Guaido managed to break his own government-imposed travel ban and head to Colombia thanks to help, he said, from members of the armed forces.

"It's a process that you don't see often, and that people don't much like because it's slow, but it can accelerate when the military and civilians see that the government could fall apart," added Salamanca.

Guaido's main backer, the United States, has ramped up the pressure on the regime with sanctions against top officials, and the promise to exempt those who recognize Guaido as their true leader.

- Military enrichment -

The problem is that the military is firmly entrenched in the echelons of power and wealth.

Of Venezuela's 32 ministries, nine are in the hands of the military including strategic portfolios such as defense, interior, agriculture, food and the state oil company PDVSA -- the country's beating heart that is responsible for 96 percent of its revenue.

As Maduro's unpopularity increased, Venezuela's military top brass found itself in control of a state bank, television, construction, mining and gas companies.

So far, only lower or medium level military personnel have deserted, the high command remains steadfast in support of Maduro.

"The desertion of the rank and file isn't going to break Maduro's system by itself," Christopher Sabatini, professor of international relations at Columbia University, told AFP.

"They need to move onto the next level: admirals, captains, colonels and generals."

Desertions, though, make it difficult for the "security apparatus to defend strategic areas," said Diego Moya-Ocampos, from London-based global information provider, IHS Markit.

The cracks haven't led to decisive shifts in the power balance, but they have become more visible.

Some 180 military personnel were arrested in 2018, charged with conspiracy, according to the non-governmental organization Control Ciudadano.

Two generals were amongst those arrested over an alleged assassination attempt on Maduro in August using explosives-laden drones.

- Pressure mounting -

Add to that, 4,300 soldiers deserted the National Guard in 2018 and 10,000 have asked to be discharged since 2015, Control Ciudadano said.

"What is happening is the most convincing demonstration of the breaking down of the armed forces' fundamental pillars," said military expert Sebastiana Barraez.

"These are soldiers who can no longer resist the pressure, who are forced to take part in actions, who reject their superiors."

Last month, 27 soldiers rebelled two days before Guaido proclaimed himself acting president.

Some posted videos to social media complaining about their barracks conditions.

Carlos Eduardo Zapata, a sergeant who defected to Brazil, spoke about the conditions in barracks.

"There's no food, there are no mattresses, us National Guard sergeants are sleeping on the floor," he said.

"We don't have enough to buy a liter (one quart) of milk for our children, the children are skinny."

Rocio San Miguel, president of the Control Ciudadano rights group, said "There's a lot of concern about the situation."

"This week there is expected to be an announcement about an increase in armed forces salaries as an incentive to loyalty," she said.

However, she added, "the military abandonment of Maduro will continue and only those compromised by serious human rights abuses will continue to support him."