"People are reluctant to leave their homes because experience tells them that nothing even happened before and that nothing will happen if they disobey evacuation orders," he said. "However, if they risk losing their animals and belongings, they'll listen."
Mexico's Popocatepetl volcano spewed a new column of ash late Tuesday, with some of the material falling on three towns while glowing rocks landed on the towering mountain's slope.
The volcano, known locally as "Popo" and "Don Goyo," belched out a cloud of ash that rose four kilometers (2.5 miles) above its crater at 8:21 pm (0121 GMT Wednesday), according to the National Disaster Prevention Center.
The ministry said "light quantities of ash" dropped on Paso de Cortes, a Mexico state community at the foot of the volcano, and the towns of Atlixco and Huejotzingo in the state of Puebla, some 23 kilometers away.
Molten rocks were thrown one kilometer away, landing on the volcano's northern slope.
The smoke was blowing toward the northeast. Mexico City is 55 kilometers (34 miles) northwest of Popocatepetl.
The volcano had already spewed some ash and rocks Tuesday morning but a senior official later reported that it had calmed down. The disaster prevention center reported low-level activity later on, including a 40-minute low-intensity tremor.
The 5,452-meter (17,887-foot) high volcano has been rumbling and spewing steam, ash and rocks sporadically for days, prompting authorities to raise the alert level and prepare for possible evacuations last weekend.
Last week, Popocatepetl covered several towns in ash, including the capital of Puebla state.
Authorities have raised the alert level to "Yellow Phase Three," the fifth of a seven-stage warning system, restricting access to an area of 12 kilometers (7.5 miles) around the volcano while preparing evacuation routes and shelters.