Peruvian authorities have been sending aid to hundreds of evacuees after declaring a state of emergency in the area near the erupting Ubinas volcano.
A dome of incandescent lava is building, experts say
Gas and cinder began spewing from the 5,672-metre (18,609-ft) volcano in southern Peru three weeks ago.
Tonnes of aid, particularly tents, water and powdered milk, have been shipped into the affected zone.
The army has been brought in to help evacuate nearby villages, although some residents are reluctant to leave.
The civil defence institute has recommended that the entire population in the district of Ubinas, about 3,500 people, be evacuated as soon as possible.
However, correspondents say many people do not want to leave their livestock and land.
So far no human lives have been reported lost, but llamas and alpacas have died from eating grass exposed to volcanic pollutants.
Peru's Institute of Geophysics has warned that a dome of incandescent lava seems to be building up in the crater.
The volcano has been spewing out acid-laden ash and smoke over a radius of 6km (3.5 miles), causing eye and breathing problems for local people.
Teams of geologists and doctors have been sent to the area to monitor the volcano and the health risks.
More than 200 people have already been forced from their homes and several thousand more are at risk, officials said.
Around 40 families have been told to leave the town of Querapi, which lies just 4km from the volcano.