Kilauea, one of the most active volcanoes in the world, has begun to erupt again, according to the U.S. Geological Survey.

Lava began to emerge from the summit of the famed volcano, located at Hawaii Volcanoes National Park on the Big Island, around 12:30 a.m. local time, prompting the USGS to raise the alert level to red.

A red alert signifies that a volcanic eruption is imminent, underway or suspected, with potential hazardous activity on the ground and in the air.

The eruption occurred about a mile south of the Kīlauea Caldera and north of the Koa’e fault system and Hilina Pali Road, within Hawaii Volcanoes National Park but in a closed, rugged area, according to the USGS.

The open fissure is more than a mile long, a USGS spokesperson told ABC News. The lava has varied in height and vigor, with some eruptions spewing up to 65 feet, the spokesperson said. Gas was also being emitted from the fissure, the spokesperson noted, and the last time there was an eruption like this was in 1974.

This eruption could continue for a few hours to a couple of days, the spokesperson said.

Officials have not yet observed a Pele’s hair — volcanic glass formation produced from cooled lava and stretched into thin strands — at the site.

Officials are closely monitoring the volcano for signs of increasing or decreasing activity, the USGS said.

Seismic activity and ground deformation beneath the East Rift Zone and Southwest Rift Zone remain low, the agency said. Current volcano activity is restricted to the summit region.

Past eruptions at Kilauea have proven to be destructive. Heavy lava flow destroyed more than 600 properties in 2018 as it traveled from the Kilauea summit to the ocean.

A mechanism similar to a “stomp-rocket toy” contributed to the severity of the lava flow that year and could affect future eruptions similarly, according to a paper published last week in Nature Geosciences.

abcnews.go.com