Guatemalan authorities cautioned pilots Monday that increased activity in the country's Fuego volcano had dispersed ash into the atmosphere.
The column of volcanic ash has risen 4,500 meters (914,700 feet) above sea level in a southwesterly direction, Guatemala's disaster response agency said.
The volcano, which is located in southwestern Guatemala, is "presenting changes in the pattern of eruptions with an increase in the number of moderate and strong explosions," it said.
The Fuego volcano, one of three active volcanos in Guatemala, had a strong eruption September 13, 2012 that prompted the authorities to evacuate of 5,500 people who live on its slopes.