ANGKOK, April 29 - Thailand flooded its predominantly Muslim south with about 1,000 soldiers on Thursday as local residents and human rights groups questioned the overwhelming force used to kill more than 100 lightly armed attackers on Wednesday.

Saying he feared retaliatory attacks, Defense Minister Chettha Thanajaro ordered two battalions of reinforcements into an area where the government's use of force has fed resentment and violence.

Interviewed on Thai television, local residents voiced anger and bewilderment at the killings, particularly an attack on a mosque in which about 30 of the men had taken refuge.

The locals identified some of the dead - mostly young men in their teens - as local villagers, including 18 members of a soccer team, according to The Associated Press.

Altogether, the government said, 108 attackers had died, along with 5 soldiers and police officers.

Much larger questions concerned the motives for the attacks on a dozen police stations and outposts early Wednesday and the identity of the people who organized them.

The attackers shouted Islamic slogans, but they also appeared to be some of the same young men who analysts said had been hired in the past to burn schools and carry out raids.

Southern Thailand, which was annexed by what was then Siam a century ago, is home to most of the 6 million Muslims in this largely Buddhist nation of 66 million people.

It seethes with vendettas, political rivalries, criminal gangs, smugglers, drug runners and a dangerous feud between the military and the police, as well as with the remnants of a separatist rebellion that was mostly quelled more than a decade ago.

"There are too many things going on there for anybody to actually point a finger and say this is the thing that caused it,'' said Saroja Dorairajoo, an expert on the region at the National University of Singapore. "The causes are multiple.''

Like other experts, she said she doubted the involvement of international terrorist groups, although members of these groups have had a presence in Thailand.

The violence, which has intensified since a well-planned raid on an armory in January, has brought an atmosphere of fear to the region.

A newly deployed security force has used brutal tactics that experts say include killings and kidnappings, heightening local anger at the largely Buddhist military and police presence in the region.

If Thailand continues to emphasize a military response to the southern unrest, a backlash could grow, several experts and human rights campaigners said.

The military said it was bracing for more violence.

"I would say the military phase has just started,'' Gen. Pallop Pinmanee, who commanded the attack on the mosque, told a radio station.

The country's top Muslim cleric, Sawas Sumalayasak, spoke out on television in support of the military's aggressive response to Wednesday's attacks and its own attack on the mosque.

"The authorities exercised reasonable restraint in dealing with the situation,'' he said. "They were patient and waited for a long time outside the mosque.''

Newspapers and television stations in Bangkok reacted with shock at the high number of fatalities.

Under a banner headline reading "Kingdom Shaken,'' The Nation, an English-language daily, said the episode "may change Thailand forever,'' and warned it could lead to "an era of constant fear, mistrust and intolerance among people of different beliefs.''

The Thai Post, a mass-circulation daily, wrote: "The government said the attackers were teenagers who were lured and hired by adults to carry out the unrest. If this information is true, and as Thailand is a civilized country, should they have been killed?''

It continued: "If the government does not understand what has caused the problem in the south and intends nevertheless to use such strong measures, it may lead to more violence that cannot be quelled.''

The United States and international human rights groups expressed concern over the killings.

"Most of the attackers only had machetes and knives,'' Forum Asia said in a statement. "So surely the well-armed soldiers and police who are trained to deal with this can handle these people, so why shoot to kill?''

Along with scores of machetes and knives, it said only six firearms were recovered from the attackers.