LIMA, Peru (AP) — The clock has run out for an estimated 40,000 illegal gold miners who had until Saturday to legalize their status in a region of southeastern Peru where fortune-seekers have ravaged rainforests and contaminated rivers. The government's vow to enforce a ban on illegal mining is raising fears of bloody confrontations.

The miners already have been clashing with police while intermittently blocking traffic on the commercially vital interoceanic highway that links the Pacific coast with Brazil, protesting government attempts to squeeze them out by drastically restricting shipments of the gasoline they use for their machinery. One miner has been killed and more than 50 wounded.

But officials insist this time they're serious about combatting the multi-billion-dollar illegal mining trade that accounts for about 20 percent of Peru's gold exports.

"We're not backing down even one inch," said Daniel Urresti, the former army officer leading the task for President Ollanta Humala.

The unrest already has left the region's cities short of food, inflating prices, and local authorities who support the miners have traveled to the capital to press for more time. They were denied an audience with Urresti and other officials.

"I don't know what's going to happen after the government deadline lapses. I think the violence will begin," said Jorge Aldazabal, the governor of the Madre de Dios region who has spent more than a week camped out on a mattress in front of a 17th-century church to protest the crackdown and demand a solution.

Peru criminalized unpermitted mining in rivers and other protected natural zones in 2012 but repeatedly delayed implementing the law, which imposes up to 12 years in jail and fines of up to $54,000 on violators.

Now, with the government preparing to host global climate talks in December and the world's eyes upon it, authorities insist they are determined to end the illegal mining, even if critics say that invites mayhem because no economic alternatives have been offered to the miners, most of them dirt-poor migrants from the Andean highlands.

Very few qualify to legalize their operations because any permission they may have to use the land is questionable at best. Some have paid bearers of reforestation permits to mine on that land. Others mine on indigenous reserves. The government says most are squatters with no claims at all.

Urresti told The Associated Press that authorities will first go after a group of about 20,000 miners centered near the interoceanic highway in an area called La Pampa. They already have been clashing with riot police sent from Lima.

Those miners, who began arriving in 2008, populate shantytowns carved into jungle along the interoceanic highway where coerced prostitution and tuberculosis thrive and the glow of welder's torches mending overworked machinery burns well into the night.

As they separate flecks of gold from the sandy, alluvial soil, the miners use mercury to bind it. Tons of the toxic metal have been dumped into rivers, contaminating fish, humans and other animals and plants.

No one knows how much gold Madre de Dios contains. But officials say more than 159 metric tons, worth more than $7 billion at current prices, have been mined in the Austria-sized region over the past decade. The region is among the planet's most biodiverse and includes indigenous tribes that shun contact with outsiders and are vulnerable to diseases.

Peru as a whole ranks sixth globally and first in Latin America in gold production

Urresti said the La Pampa group is bankrolled by about 50 individuals.

"They move $2.9 billion dollars a year. It's a very big mafia," Urresti said, refusing to identify the individuals by name. He said prosecutors are gathering evidence against them for crimes including money-laundering.

In September, the government moved for the first time against companies accused of refining illegally mined gold. Previously, only illegal dredgers in Madre de Dios had been targeted.

Authorities destroyed 400 trucks and dynamited 13 illegal refineries valued at more than $30 million in the coastal towns of Chala and Nazca, far removed from Madre de Dios.

In an unprecedented move, it also seized 2 tons of gold and installed machines designed to detect gold at five airports in the country's southeast.

"They know we're serious and that we're going to smash the most expensive machinery and that we won't be stopped," Urresti insisted.

For their part, the miners interviewed by the AP at protests in Lima said they're unable to comply with government legalization requirements.

"What are we going to do if they boot us out?" said Reimundo Barrios, a 51-year-old miner who moved to Madre de Dios in 1980. "I sent my son to university doing this work."