The Fire Volcano in Guatemala is spewing incandescent rock and ash on surrounding communities, officials say.
Disaster preparedness office spokesman David de Leon said authorities have put the southern Guatemala area on alert, although no evacuations have been made so far.
Karina Lopez, a resident of nearby Antigua, said on Saturday that ash mixed with a drizzle to reduce visibility and that the rumblings continued.
The 3763m-high volcano sits on the border of the Guatemalan states of Escuintla, Sacatepequez and Chimaltenango.
The national co-ordinator for disaster reduction issued instructions urging people to take shelter, wear masks, cover water tanks and be aware of evacuation routes.
Firefighters were standing by.