LATACUNGA • Ecuador's President Rafael Correa has declared a state of emergency as the Cotopaxi volcano rumbles to life and prompts evacuation orders in villages at risk of landslides.

"As a precautionary measure, 400 people have been evacuated," he said in his radio and television address last Saturday.

The 5,898m-high volcano is considered one of the most threatening in the region - both because of its size and because it is so close to well-populated towns.

It started to stir last Friday, registering several small eruptions and shooting plumes of dust and ash 8km into the sky.

By declaring a state of emergency, the president can direct resources and deploy military personnel to aid affected communities.

Earlier, officials ordered what they called precautionary evacuations in villages near the volcano, warning residents about potential landslides consisting of volcanic debris, or lahars.

Residents of towns and river settlements in Cotopaxi province, just 45km south of the country's capital of Quito, were told to clear out, said Mr Pablo Morillo, who heads the Risk Management Office.

In the city of Latacunga, which is home to about 170,000 people, sirens sounded as residents fled frantically, packing food, water and pets into cars.

The authorities maintained a yellow alert, which is a mid-range warning, and said it would remain in place as long as the volcano continued to stir.

"We will maintain the same alert, but since there are still no lahar flows, the evacuation order is only preventive," Mr Morillo said.

Quito mayor Mauricio Rodas said a million surgical masks would be distributed across the city of 2.3 million people, to prevent inhalation of falling dust.

Cotopaxi is one of eight active volcanoes in Ecuador. The country is part of the so-called Pacific Ring of Fire, which makes it prone to seismic and volcanic events.

AGENCE FRANCE-PRESSE