Scores of rescuers began excavation work on Saturday at a mine in southern Ecuador where a cave-in trapped four workers 500 feet (150 metres) underground in the latest accident to hit the industry in Latin America.
In scenes reminiscent of last week's rescue of 33 miners in Chile, local residents and distraught relatives gathered at the small gold mine at Portovelo near the Peruvian border.
There was still no word on whether the four night-shift workers had survived the tunnel collapse early on Friday. Officials blamed the accident on water leaks.
"The rescue operation is going to take another 24 hours," President Rafael Correa said on Saturday morning.
Rescue efforts were focused on boring a hole to insert a small probe with a camera inside to determine the men's fate and make contact if they have survived, officials said.
In Chile, the 33 miners survived for two weeks on limited rations until rescuers made contact. Their rescue, after more than two months deep under remote desert, triggered euphoria across the continent.
It also put a spotlight on mining safety in Latin America where there are still many accidents though standards have improved radically in recent decades compared to the horrors of past centuries.
One of the worst accidents of recent times took place in Colombia in June, when more than 70 miners died after a gas explosion at a coal mine.