PADANG BESAR, Thailand -- Thai police dug up 26 bodies from dozens of shallow graves at an abandoned mountain jungle camp that's been linked to human trafficking networks, which activists say are "out of control" in the Southeast Asian country.

A lone survivor, hospitalized with severe malnutrition, told authorities smugglers escaped days earlier with about 100 Rohingya Muslims, a long-persecuted religious minority in neighboring Myanmar.

Police Gen. Jarumporn Suramanee, who oversaw the excavations in southern Thailand, said Saturday it would take time to determine the victims' identities and cause of death.

"We will have to wait for the DNA test results and analysis from other evidence," he said. He said 32 graves were found scattered in Padang Besar, a sub-district in Songkhla province, but some turned out to be empty. He did not expect the death toll to rise above 26.

The discovery of a hidden mountain camp in southern Thailand, long considered a regional trafficking hub for migrants seeking a better life in third countries, was a reminder little has changed despite assurances by authorities they are addressing the root causes.

A government spokesman, Maj. Gen. Sansern Kaewkamnerd, issued a reaction Saturday, saying his country was determined "to eliminate every type of human trafficking and block Thailand from being a transit point." Those behind the camp will be "severely punished," he added, regardless of whether they were common criminals or corrupt officials.

Human Rights Watch, meanwhile, called for an independent investigation with U.N. involvement to determine what happened at the site.

"Trafficking of persons in Thailand has long been out of control," said Brad Adams, Asia director at Human Rights Watch. "The finding of a mass grave at a trafficking camp sadly comes as little surprise."

Last June, the United States put Thailand in its lowest category -- Tier 3 -- in an annual assessment of how governments around the world have performed in fighting human trafficking. The ranking took into account the smuggling of Myanmar's Rohingya community, as well as cases of migrants from neighboring countries who are forced or defrauded into working against their will in the sex industry, commercial fishing, garment production, factories and domestic work.

Thailand has promised action to get off the blacklist, but recent revelations by the AP that some of its fishing vessels were treating men from Myanmar, Cambodia and Laos as virtual slaves have further dented the country's reputation.

Authorities discovered the camp Friday, acting on a tip. Police and rescuers reached the mountain camp on foot, and found a clearing with 39 bamboo huts, two dozen sleeping quarters and some makeshift kitchens and toilets.

They also found one corpse covered with a blanket and a weak, ailing male survivor identified as a Bangladeshi national before beginning to dig up graves. The survivor told police that about 100 Rohingya were held there and taken away just days before police arrived, said local police commander Col. Weerasant Tharnpiem.

Police could not immediately confirm if the captives were Rohingya Muslims.

Members of the religious minority have for decades suffered from state-sanctioned discrimination in Myanmar, which is predominantly Buddhist. Mob attacks in the last three years have left up to 280 people dead, sparking one of the biggest exoduses of boat people since the Vietnam War.

More than 100,000 men, women and children have boarded ships in the Bay of Bengal since June 2012, said Chris Lewa, director of the Arakan Project, which has monitored the boat movements more than a decade.

That number includes both Rohingya from Myanmar and a growing number of Bangladeshis.

Their first stop is almost always Thailand.

Lewa believes there are around 800 people still in jungle camps in Thailand. However, there has been a change of tactics recently, one that appears to be putting them at even greater risk.

Instead of jungle camps, Rohingya and Bangladeshis have in recent months been taken to large ships while they wait for ransoms to be paid, said Lewa, who estimates that 7,000 to 8,000 migrants are currently parked off the coast or in nearby international waters.

Their health is inevitably deteriorating quickly, she said, adding that there are growing reports of deaths. A 15-year-old survivor told Arakan Project last week that during his own two months at sea, more than 30 people died on three different boats.

He said the bodies were all thrown overboard.