QUITO, Ecuador (Reuters) - A steady glow from the crater of Tungurahua near the tourist town of Banos 105 miles south of Ecuador's capital Quito could mean the volcano is near violent eruption, scientists said on Tuesday.

``In the past two weeks it has been glowing almost all the time. This is very important and is a sign of very intense activity. We have to be very careful,'' Alex Garcia, a geologist at the National Geophysics Institute in Quito, told Reuters.

Twenty-thousand people were evacuated from Banos in October 1999 when scientists declared an ``orange alert.'' This meant it could be just days or weeks before a major eruption by the conical Tungurahua -- whose name means ``Throat of Fire'' in the Quechua Indian language.

Tungurahua erupted 80 times in the last 3,000 years, scientists believe. Regular explosions have shaken the 16,500-foot mountain which looms over Banos for months.

``It is very difficult to predict when you could have a large explosion. The volcano is already erupting; any explosion that occurs could be a big one and generate effects like fire balls that would be much more dangerous,'' said Garcia.

With its hot springs and waterfalls tumbling down green slopes, Banos is one of Ecuador's biggest tourist attractions. Just below the equator but at 5,900 feet above sea level, it enjoys a crisp climate of eternal spring and a spectacular view of snowcapped Tungurahua.

Ecuador, afflicted in recent years by a brief military coup, massive El Nino storm damage and unable to pay its debts, has 31 active volcanoes.

Quito is surrounded by a ``volcano alley'' of nine of the fire mountains, one of which, Guagua Pichincha, began to shower the capital with volcanic ash in 1999. Quito residents stopped in their tracks when an atomic-bomb-like mushroom cloud rose from the volcano in early October 1999.