In his weekly address to the South American nation on Saturday, Ecuador's President Rafael Correa announced the move to give the government the ability to mobilize financial resources and security forces in the case of an eruption.

"We declare a state of emergency due to the unusual activity of Mount Cotopaxi," Correa said, adding "God willing, everything will go well and the volcano will not erupt."

Cotopaxi, which is about 50 kilometers (30 miles) south of the capital Quito, began to rumble Friday - several small explosions were registered and plumes of ash shot into the sky. Correa said those minor explosions led to evacuations from nearby towns.

"As a precautionary measure, a total of 400 people have been evacuated," he said.

Officials have warned residents of a heightened risk of lahars, or landslides of volcanic debris. According to the AFP news agency, Quito Mayor Mauricio Rodas said a million face masks would be distributed across the city of 2.3 million, to prevent people inhaling dust from the volcano.

The national park in which Cotopaxi is situated, a popular destination for tourists wishing to admire the 5,897 meter (19,350 feet) high active volcano, has been closed, also as a precaution.

Political rumblings, too

Protests and strikes broke out this week against Correa's planned tax hikes and moves to change the constitution so he can run for president again when his current term expires in 2017.

In theory, the state of emergency declaration means limits could be imposed for a time on freedom of assembly and news coverage.

se/bw (dpa, AFP, Reuters)