Falling water levels have raised hopes that rescuers will be able to enter a flooded Mexican mine, possibly on Wednesday, to look for 10 trapped workers, the government said.
Authorities using an underwater drone equipped with a camera decided that it was still too dangerous to enter the mine in Agujita in the northern state of Coahuila.
But by Wednesday or Thursday, the water level is expected to have dropped to 1.5 meters (around five feet), so "divers and rescuers will be able to enter," President Andres Manuel Lopez Obrador told reporters.
Several hundred rescuers, including soldiers and military scuba divers, are taking part in efforts to save the miners, whose relatives were increasingly anxious nearly a week after the accident.
Images gathered by the drone on Monday showed obstructions and water turbulence, making it still too risky to go inside, civil defense national coordinator Laura Velazquez said.
The focus so far has been on pumping out water from the 60-meter (200 feet) deep mine.
The water in the shafts has fallen significantly, from more than 30 meters initially, but was still at least 10 meters deep, officials said.
According to authorities, the miners were carrying out excavation work when they hit an adjoining area full of water.
Five workers managed to escape from the crudely constructed mine in the initial aftermath of the accident on August 3, but there has been no contract with the others.
Coahuila, Mexico's main coal-producing region, has seen a series of fatal mining incidents over the years.
The worst accident was an explosion that claimed 65 lives at the Pasta de Conchos mine in 2006.
Last year, seven miners died when they were trapped in the region.