Rescuers have intensified efforts to reach at least 34 people trapped by a mine collapsed in northern Chile.
Officials said on Friday that they had not yet been able to establish contact with those trapped in the San Esteban mine, near the city of Copiapo in the Atacama desert, and the miners' conditions remain unknown.
The copper and gold mine, located about 800km north of the capital Santiago, collapsed on Thursday.
Chile's National Emergency Office said around 130 rescue workers have been deployed to try to help the miners.
It said the mine workers were thought to be at a depth of about 450 metres, adding that it was possible they had managed to reach an underground shelter, which contains three days worth of food, water and oxygen.
Camila Merino, Chile's labour minister, joined rescue workers and relatives of the miners at the scene of the collapse on Friday.
She said due to the blockages caused by the collapse, rescue workers were trying to access the mine through ventilation shafts.
"We must work very carefully because if we create a new collapse it will put rescuers at risk and harm the ability to get people out quickly", she said.
'History of accidents'
Major mining accidents are not frequent in Chile because of tight government controls.
Compania Minera San Esteban Primera, the mine owner, said it was unclear what caused the collapse, but insisted that all necessary precautions had been taken.
Felix Medina, a local union representative, however, told the Reuters news agency that the San Esteban mine had a history of accidents, with at least 13 deaths on site recently.
"This is an area with a lot of mining activity but the authorities don't have the resources for proper supervision," he said.