A powerful mechanical digger has begun digging a rescue shaft at a collapsed Chile mine where 33 men are trapped about 700m below ground.

Chilean officials on Wednesday broke the news to a desperate group of trapped miners that they could be stuck in their collapsed mine for months.

Mobs of angry survivors of the Chile earthquake have set fire to shops in the devastated city of Concepción as troops battle to keep order.

Chile’s earthquake death toll topped 700 on Sunday as rescuers searched for survivors and the extent of the disaster became clear in coastal areas.