Mexico\'s Popocatepetl volcano rumbled Saturday with explosions and expulsions of ash and gas, prompting authorities to bar people from getting close to a crater that is within sight of Mexico City and many of its 19 million residents. The country\'s National Center for Disaster Prevention reported that following 12 \"low-intensity\" emissions of a small amount of water vapor and gas -- there was \"an exhalation with some explosive component\" around 9 a.m. (10 a.m. ET). This was \"followed by a spasmodic tremor ... with moderate to large amplitudes, which has been accompanied by a continuous emission of ... ash and water vapor,\" according to the government agency quoted by CNN. At that time, the emissions had gone at most 400 meters (1,300 feet) above Popocatepetl\'s crater. Ash had fallen on the towns of San Nicolas de los Ranchos and Huejotzingo, as well as the northern part of the city of Puebla.