Weeping family members crowded outside a Thai military camp Wednesday, demanding information about 78 Muslim men who were crushed to death Monday after being arrested and forced onto army trucks.

Some villagers scanned long lists of survivors' names at the army base, and others reclaimed victims wrapped in body bags to be transported home.

As relatives began to bury their dead, local Muslim leaders warned that the tragedy could escalate tension in Thailand's southern region, where Muslim separatists early this year revived an insurgency against domination by authorities in Bangkok.

The deaths occurred after troops seized about 1,300 men during a demonstration in Tak Bai near the Malaysian border and crammed them into army trucks for a five-hour drive from Narathiwat province to the camp in Pattani, the regional center for Thailand's mostly Muslim provinces in the south.

Prime Minister Thaksin Shinawatra defended the military's actions in subduing the demonstrators, who were protesting the detention of six men accused of providing weapons to Muslim separatists. But facing sharp criticism from political opponents and human rights groups, he acknowledged that soldiers had made mistakes after the arrests and said he had ordered an investigation.

"It was an accident during transport which happened because the time and situation were pressing. There were few vehicles. That was why they were crammed together," Thaksin told reporters. Thai officials said the prisoners had been laid on top of each other.

Thaksin has been accused repeatedly of using excessive force in dealing with unrest in the south. About 4 percent of Thailand's 65 million people are Muslim. They have complained about chronic poverty and discrimination in the predominantly Buddhist country.

In Narathiwat, a computer salesman said that he had retrieved the body of his younger brother but that it was difficult to identify him because his head had been badly beaten or crushed.

"I hardly recognized his face, but I could recognize his clothes," said the man, Jalaludin, who did not give his family name.

The brother, Razee, 22, a recent Islamic school graduate who did odd jobs along the border, had been near the front of the crowd when security forces opened fire and charged at protesters, according to his relatives.

"He didn't want to join in the demonstration. It's just that the location was near our home and he was curious to see what was happening," said Jalaludin, 38.

Security forces had initially tried to disperse the demonstration by using water cannons and tear gas but then opened fire before advancing to make mass arrests, Razee's relatives said. Television news showed that some protesters were forced to crawl across the road to waiting trucks, bare-chested with hands tied, while troops kicked them and struck them with rifle butts.

"We're angry about what happened to my brother, but what can my family do? Nothing," Jalaludin said.

Thai officials reported at least 88 deaths, including six shot and killed during the demonstration, three bodies recovered from a nearby river and one victim who died in the hospital. Some villagers alleged that the number killed was even higher.

By Wednesday evening, 22 of the victims who died in the trucks remained unidentified and unclaimed by family members. Many villagers in Narathiwat province were frantic for information but reluctant to travel to Pattani, fearing they would not make it home before a nighttime curfew imposed by Thai authorities Monday evening.

Local Muslim leaders said they had reached agreement with Thai officials to start the ritual funeral washing of the remaining bodies early Thursday. Bodies unclaimed later in the morning would be transported to Narathiwat and buried in a mass grave, leaders said.

"Of course people are angry. They say the government overreacted. Now there will be more violence," said Nideh Waba, chairman of the Islamic schools association in southern Thailand.

The Pattani United Liberation Organization, a separatist group that has remained largely dormant for two decades, vowed Wednesday on its Web site to avenge the deaths by launching attacks in Bangkok.

The violence this week jarred many in southern Thailand who had hoped government forces would act with restraint after clashes in April that left at least 112 people dead in a single day. Those battles included raids on police posts in three southern provinces, and a raid by security forces on Pattani's historic Krue Se Mosque that killed 32 insurgents holed up inside.

"We thought the Krue Se incident in April would be the last incident of this kind," said Abdulrahman Abdulsamad, chairman of the Islamic Council of Narathiwat. "But we saw it again on Monday. Now I can't imagine what response will come next."

Special correspondent Somporn Panyastianpong contributed to this report.

At a Thai army camp, families scan a list of protesters' names. Officials reported at least 88 deaths, including 78 men who were crushed in trucks.