Activity at Guatemala’s Fuego volcano, which began Monday morning and prompted widespread evacuations, is gradually declining, authorities said Wednesday.

However, the National Coordinator for Disaster Reduction, or CONRED, urged people to remain cautious as rainfall from a tropical wave moving from the east could trigger potentially deadly volcanic mudflows known as lahars.

CONRED also confirmed that some people evacuated between Monday and Tuesday had voluntarily returned to their homes.

“But the eruptive activity continues, and it is recommended to follow the authorities’ instructions regarding preventive evacuation,” the agency said.

Around 1,700 people have been evacuated from at least 18 communities on the slopes of Fuego, or the Volcano of Fire, since the eruption began Monday. No deaths or damage have been reported.

Live broadcasts of the volcano have shown periods of clear conditions followed by ash emissions. Early Tuesday, the volcano sent lava about 300 meters (984 feet) into the air, prompting red alerts and evacuations, the closure of a highway and the suspension of classes in three departments.

Fuego, one of Guatemala’s most active volcanoes, stands 3,768 meters (12,300 feet) high and is classified as a stratovolcano, a tall, cone-shaped volcano formed by layers of hardened lava, ash and rock.

It is located between the departments of Escuintla, Chimaltenango and Sacatepéquez in southern and central Guatemala, about 53 kilometers (33 miles) from the capital.

An eruption on June 3, 2018, killed hundreds of people, destroyed an entire community and affected up to 1.7 million people. Another eruption last year also prompted preventive evacuations.