MEXICO CITY - A volcano outside Mexico City grumbled for a third straight day Saturday, spewing ash, gas and water a mile above its crater as a moderate-level alert remained in effect.
The government warned people to stay at least six miles away from the Popocatepetl volcano, which had erupted 76 times by Saturday afternoon and was expected to continue belching ash over the next few days, the National Center for the Prevention of Disasters said.
The emissions do not posed a threat to population centers in the area, it said.
Scientists began to observe a tremor in the volcano following an eruption Thursday that spewed ash up to 25 miles. The tremor indicated a buildup of energy that could lead to further eruptions, they said.
Communities in the state of Puebla have reported light ash falls in recent days from the Popocatepetl (Poe-poe-kah-TEP-a-til) volcano.
The 17,886-foot volcano is about 40 miles southeast of Mexico City. It has been spewing vapor, ash and rock intermittently since December 1994 after lying largely dormant since 1927.
In an unrelated incident, the Colima volcano in western Mexico shot smoke hundreds of feet late Friday but later calmed down and posed no threat to area residents.
