MEXICO CITY (AP) _ Red-hot rocks began rolling down the slope of a volcano that has been spewing smoke, ash and vapor for days, prompting authorities to evacuate a hamlet in western Mexico on Tuesday.

Residents of Yerbabuena, near the Volcano of Fire, piled onto buses that took them to shelters in towns further away from the 12,533-foot volcano in Colima state about 300 miles west of Mexico City.

``There is a lot of fog, so the peak is not visible from the ground, but a reconnaissance aircraft is completing a survey of the volcano.'' said civil defense official Jose Torres.

Volcanologists say that a huge dome of lava inside the crater could either collapse, sending lava and rock down the peak's southern flanks, or explode, launching rock and ash into the surrounding area.

The Volcano of Fire last erupted in 1999, sending glowing rock three miles down its slopes, but no injuries were reported.

About 300,000 people live within 25 miles of the volcano, a radius that includes Colima city, the state capital, but lava flows have never reached populated areas.

Soldiers helped Yerbabuena's residents load their possessions on buses, and some soldiers remained behind to guard against looting.