Mexican Peace Commissioner Manuel Camacho Solis said Friday there had been "important advances" in efforts to end a 14-day peasant uprising in the southern state of Chiapas, but he warned that the peace process could be a long one.

As Camacho pursued peace, fighting was dying out in the troubled region, the Mexican army said. A government official said that helicopters on loan from the United States to assist Mexican anti-drug operations had been used to support the government's counterinsurgency campaign.Camacho, named by President Carlos Salinas de Gortari earlier this week to seek an end to the bloody rebellion by the self-styled Zapatista National Liberation Army, said he was returning to Mexico City Friday to brief the president.

"I think things are taking a suitable course. There are important advances," Camacho told a news conference before ending a three-day visit to the region.

Camacho has met church officials and Indian representatives during his trip but refused to say whether he has had contact with the elusive rebels.

The Zapatistas launched their revolt on New Year's Day by briefly seizing this colonial city and several nearby towns and villages. Most have since fled into the heavily forested mountains. More than 100 people have died in the conflict.

The Mexican army said fighting was dying out in the troubled region, although troops came under brief sniper fire Thursday. The army is observing a unilateral cease-fire ordered by Salinas Wednesday under which troops may only open fire if they are attacked by the rebels.

In Las Margaritas, a small town about 50 miles from San Cristobal held by the rebels in the first days of the uprising, parish priest Mauricio Olvera said 100 trucks loaded with soldiers passed through the town Thursday on the way to Guadalupe Tepeyac, where refugees reaching Las Margaritas said the rebels still have a strong presence.

Townspeople said the army was gathering in a town between Las Margaritas and Guadalupe Tepeyac called El Momon. The road to Guadalupe Tepeyac was cut off Friday by an army checkpoint a few miles outside Las Margaritas.