Illegal mining operations have sprung up all over the Amazon. This is a mining site in the Madre de Dios region of Peru. Mario Tama PUERTO AYACUCHO, Venezuela (Reuters) - From the air, the thick green canopy that covers the Venezuelan Amazon is pocked with ever more frequent small holes.

On the ground, at 40 degrees Celsius (104 F) in the shade, crews of Brazilian, Colombian and Venezuelan miners tear through one of the areas of greatest biodiversity on the planet in their hunt for gold, diamonds and coltan.

Those riches are then smuggled out of the country, local authorities say, with the aid of left-wing Colombian guerrillas who take a share of profits. Some locals accuse money-hungry members of Venezuela's military of also helping out.

A tripling of the value of gold over the last decade has led the illegal business of unlicensed mining to flourish, knocking efforts by Venezuela's government to check deforestation.

Foreign and local groups fighting for the rights of the region's indigenous inhabitants estimate that there are as many as 4,000 illegal miners working in the area near the borders with Colombia and Brazil.

Liborio Guarulla, a 59-year-old opposition politician who has been governor of Venezuela's Amazonas state for the last 12 years, said many of the illegal miners are protected by Marxist guerrillas of the Revolutionary Armed Forces of Colombia, or FARC.

The FARC is funded largely by the illegal cocaine trade in Colombia. Some of its units are active inside Venezuela, largely to seek sanctuary from Colombian military offensives at home.

The guerrillas received ideological support from Venezuela's late leader Hugo Chavez, who shared their leftist cause. The government in Caracas denies there has ever been any practical aid.

Still, Guarulla says members of the Venezuelan armed forces help the FARC and the miners in the Amazon.

"The illegal gold mining is done, to some extent, with the approval of the armed forces," the governor, a member of the Baniva ethnic group, told a group of about a dozen foreign journalists who visited the state capital Puerto Ayacucho, 335 miles south of Caracas.

"When the indigenous people complain, there are reprisals (from the miners) immediately."

Spokespeople for indigenous groups accused the miners of attacking, and sometimes killing, their people.

Government officials did not respond to requests for comment on the allegations of corruption. In the past they have denied similar accusations and said that on the contrary, troops defend the environment and local tribes.

It was not possible for Reuters independently to check the allegations made against the military.

President Nicolas Maduro has dismissed Guarulla as "very corrupt" and "very drunk," though the governor says he is tee-total.

'LIKE SLAVES'

Indigenous rights groups and local officials say the illegal miners see the region's indigenous Yanomami tribe and others as cheap, or nearly free, labor for their sites.

"In several communities we've found Yanomami with numbers written on their shoulders," said Luis Shatiwe, a 30-year-old Yanomami leader who heads one local rights group.

"They keep them like slaves," he said via a translator in his native tongue, speaking at an event held in a Puerto Ayacucho school to mark the 10th anniversary of a massacre of his tribespeople by illegal miners.

It was not possible to speak to the illegal miners themselves, who work deep in the forest. About a dozen indigenous people interviewed in Amazonas accused some illegal miners of attacking tribespeople who confronted them - with no apparent fear of consequences from the authorities.

"Why would you complain, when two days later you see the prospector walking happily down the street?" asked Maria Perez of the Hoti tribe, who said insecurity had forced her to move to the city from her jungle home near the Brazilian border.

"There's no authority here to protect us."

Allegations that FARC rebels are in Venezuela have caused severe diplomatic disputes for years between Colombia and Venezuela. Since 2010 both governments have sought to play down the issue as ties improve.

In San Fernando de Atabapo, a hot, dusty town of 10,000 people about 135 miles upriver and south of Puerto Ayacucho, residents refer to the Colombian guerrillas, with a degree of sympathy, as "the boys."

"They come to the town for gasoline, oil and other provisions, and then disappear into the jungle again," said Hassan Fadel, an 89-year-old Lebanese businessman who has spent half his life living in San Fernando de Atabapo.

Speaking at his small shop next to a National Guard military post, he said that in the past the rebels used to visit in uniform and demand whatever they needed. Today, he said, they come in civilian clothes and with cash to pay for the food, fuel and outboard motors that they carry away.

It was not possible to seek comment from the FARC rebels.

At the National Guard post, one young soldier accused some officers of profiting from the smuggling of guns, drugs and minerals out of Venezuela, mostly by night along the Orinoco River in boats making their way up to the Caribbean coast.

From there, trafficking experts say the goods are transferred to larger ships and small planes before being sent to buyers in the United States, Europe and elsewhere.

"Many of the bosses conceal these activities because they are conspiring with the rebels," said the soldier, who declined to be named and only spoke when his superiors were not around.

National Guard officials declined to comment specifically on that allegation, but say they constantly carry out operations in the area against the rebels and illegal mining.

Nationwide, illegal mining in Venezuela is thought to produce about 12 tons a year of gold, or roughly double the amount produced by the legal, regulated sector.

'MEN IN UNIFORMS'

Not everyone is convinced of the Colombians' presence, however.

"We see men in military uniform going upriver, but we can't know who they are," cautioned Ramon Garrido, an independent politician in Autana, a town halfway back to Puerto Ayacucho. "We don't have any proof."

Deforestation is a big concern, with the Venezuelan government's figures showing it has increased to 1,100 square km annually in recent years, an area roughly the size of Rio de Janeiro.

While that is much less than the more than 5,800 square km that was cut down last year in Brazil, Maduro's administration says it aims to plant some 20 million new trees in deforested areas before the end of 2015.

Flying over the rain forest in a small plane, the Amazonas governor, Guarulla, said he hoped those efforts could, bit by bit, fill in the holes torn by the prospectors.

He also hoped talks in Cuba between Colombia's government and the FARC could lead to a peace deal and an eventual rebel demobilization. He doubts, however, that all the FARC would go home and give up their profitable business, even if they give up their guns and uniforms.

"Is it possible that if there's a peace deal with the FARC then they will leave Venezuela?" Guarulla asked. "Or will they continue with their business? Because it is a good one."

(Reporting by Diego Ore; Writing by Daniel Wallis; Editing by Kieran Murray and Andrew Hay)