The Popocatepetl volcano which towers over Mexico City began rumbling again today, shooting a blast of ash about two miles (3km) above its crater.
The ash cloud drifted first to the west and then turned back east toward the city of Puebla, Mexico’s national disaster prevention agency said.
The 17,886ft (5,450m) mountain shook for several minutes before the ash burst out.
The agency urged people to stay at least seven miles (12km) from the crater, which is about 40 miles (65km) south-east of Mexico’s capital.
Puebla state civil defence director Jesus Morales told a local television station that the cloud “has a high ash content, but it doesn’t represent a risk”.
“A little ash could fall in Puebla city,” he said.
Both Mr Morales and federal civil defence co-ordinator Laura Gurza warned residents in the region that they should not wet down any ash which falls before sweeping it away.