SAN CRISTOBAL DE LAS CASAS, Mexico (AP) _ Rebel leaders came down from their mountain hideouts, government officials left their city offices, and the two sides opened their first substantive peace talks Wednesday since the months after a January 1994 Indian uprising.

Dozens of unarmed military police ringed a 16th century convent as government negotiators, Mexican opposition leaders and Indian rights activists discussed what caused the uprising among impoverished Indians in Mexico's southernmost state of Chiapas.

For six months, the government and the guerrillas have talked about how to talk. Now, hopes were running high that a peace accord could be reached.

Talks are expected to last for several days. Then in a few weeks, 15 negotiators from each side will begin a second round, wrapping up what hundreds of representatives are discussing this week.

Sixteen ski-masked rebels arrived in San Cristobal de Las Casas on Wednesday in four-wheel drive vehicles, ferried in from remote mountain hideouts by the Red Cross. The rebels' top military leader, Subcomandante Marcos, did not attend, apparently fearing he would be arrested.

Escorted by police cars with blaring sirens, the guerrillas made a dramatic entrance, though none as stunning as their surprise occupation of this town on Jan. 1, 1994. At least 145 people were killed before a cease-fire was declared 12 days later.

Dozens of Indian supporters clapped as the rebels entered the old stone convent in an almost festive air.

The top government negotiator, Marco Antonio Bernal, said he was optimistic these talks would lead to a lasting peace.

``(This) will allow us to make progress on the problems at the root of the conflict,'' Bernal told The Associated Press. ``We hope that the discussions ... can lead to solutions.''

The uprising focused national attention on the problems of Mexico's Indians, many among the country's poorest people, who receive substandard education, housing and medical services and face discrimination in getting jobs.

Bartola Morales Garcia, from neighboring Oaxaca state, was among scores of indigenous activists from around Mexico who came not just to solve issues in Chiapas, but problems nationwide.

``We are trying to find a solution to the conflict and resolve the problems of the indigenous people at a national level, because all of us Indians have problems, not just those in Chiapas,'' said Morales Garcia.

Wearing a white cotton shift with brightly embroidered geometric designs, she was one of dozens of Indian negotiators in native dress.

The meetings are the first substantive talks since peace talks in February 1994.

That month, the two sides a tentative accord on rebel demands for better health services, education, housing and respect for indigenous communities. Rebel supporters rejected that pact in June 1994 as being too favorable to big landowners, and the rebellion has smoldered since.

The latest negotiations come after state elections in Chiapas on Sunday illustrated the depth of disenchantment with Mexico's 66-year ruling Institutional Revolutionary Party, or PRI.

With 89 percent of precincts counted, the PRI led most Chiapas races with 48 percent of the vote, the lowest margin ever in state history. The PRI has traditionally received 90 percent of the ballot, often through fraud.

Abstention from the vote ran as high as 80 percent in some communities.