Ecuador's Tungurahua volcano has spewed gas and ash for a fourth straight day, forcing nearby residents to evacuate their villages.

Emergency officials said Monday that at least 1,600 people have taken refuge in shelters.

Tungurahua, 130 kilometers south of Quito, has covered farmland and villages with volcanic ash. The president of a farmer's association says area farmers are losing their crops.

The 5,000-meter-tall volcano sent huge columns of ash into the air in 1999, forcing the evacuation of 17,000 residents of the town of Banos to the north.

Historical eruptions of the volcano have been accompanied by strong explosions and by lava flows that reached populated areas at the volcano's base.

The last major eruption was in 1918.

Some information for this report was provided by AFP and Reuters.