MEXICO CITY (AP) _ A Mexican volcano spit a column of ash 2 1/2 miles into the air and showered red-hot rock onto the flanks of the peak.

The Popocatepetl volcano _ whose name means `Smoking Mountain' in the Aztec language _ had this week been relatively quiet until Thursday's eruption, which was similar to last week's blasts.

Ash showers were expected after the one-minute eruption from the 18,000-foot volcano, located just 50 miles southeast of Mexico City, the National Center for Disaster Prevention reported.

Authorities said there was no immediate risk to the 300,000 area residents. About 15 million people live within a 50-mile radius of the volcano, which has been active since 1994 and regularly emits gas and steam.