About 260 people were ordered Thursday to evacuate their small village as the Ubinas volcano in southern Peru continued to spew acid-laden ash and vapors and its crater increased in size.

"At this time we are directing the village of Querapi to evacuate the nearly 80 families that live there," said Cristala Constantinides, regional president of the Moquegua department, told The Associated Press by telephone.

A thick plume of white smoke billowed from the crater, located 760 kilometers (470 miles) southeast of the Peruvian capital of Lima.

Seismic activity has been building up since February in the volcano, which erupted last Friday, sending a plume of ash some 800 meters (2,640 feet) into the air.

Leonides Ocola, a volcanologist with Peru's Geophysics Institute, told the AP the circumference of Ubinas' crater had increased 40 to 50 meters (132 to 165 feet), according to measurements taken Wednesday, a sign that a larger ash eruption could be on the way.

"There is an imminent danger," said Constantinides, who added that trucks and four-wheel drive vehicles were being sent to pick up the villagers, who live two kilometers (just over a mile) from the volcano, and transfer them to outlying communities farther away.

More than 640 families from six villages and hamlets around the volcano have been affected by the ash and vapors, with residents suffering eye and respiratory problems, officials said.

Between 40 to 60 livestock, including vicuna and llamas, died near the slopes of the crater, and many more were reported ill, probably from drinking acid-contaminated water or eating ash-coated grass.

Constantinides said she hoped the orange alert would prompt Peru's central government to send medicine, face masks and other materials to the zone.