Ecuador's government is urging four villages to evacuate because of increased activity in the Tungurahua volcano not far from the country's capital.
Authorities in the South American nation say about 700 people live in the mainly farming communities on the slopes of the volcano in the Andes.
Ecuador's Geophysical Institute says increased activity that began Sunday is billowing columns of ash, sending superheated clouds of gas down the slopes and cascading hot rocks from the summit.
The agency said Monday that it is recording a gradual accumulation of lava in the mountain.
The 16,480-foot (5,023-meter) volcano is in a sparsely populated area about 84 miles (135 kilometers) southeast of the capital, Quito. It has been active since 1999.