Some victims of last week's flooding remain in danger, still trapped on islands surrounded by torrents fed by a week of rain, authorities said Saturday.

President Ernesto Zedillo made a helicopter tour of the damaged areas on the Pacific Coast of southern Chiapas state, where more than 100 people died, 20,000 were forced from their homes and 600,000 residents were cut off by downed bridges and washed-out highways.Zedillo was surrounded by weeping women in the mountain town of Motozintla, about 35 miles north of Tapachula, where a local official said 12 people died and 18 were missing.

"Don't lose hope," he told relatives of the victims. "After many days of national disaster, the first signs of help are getting through," he said.

Before breaking into tears, Flavio Vasquez told Zedillo that "my two children and wife are buried. Our house collapsed. They have not found them."

Miguel Valdez Galan, the government's emergency response director, said helicopters were fanning out across the coast.

"We know what the damages are and we have them prioritized," Valdez Galan said, noting it may take 15 to 20 days to restore land routes to 60 cut-off villages and towns in Chiapas.