Hawaii's Kīlauea volcano was erupting in "full swing" late on Wednesday, the US Geological Survey (USGS) said.
"What was once a cooling lava lake is now a new fissure eruption," USGS Volcanoes said in a tweet.
The US Geological Survey Hawaiian Volcano Observatory (HVO) elevated Kīlauea's volcano alert level from "WATCH" to "WARNING" and its aviation color code from "ORANGE" to "RED" as the new eruption and associated hazards are evaluated, USGS said.
The latest alert level and color code imply that a hazardous eruption is "imminent, underway or suspected," according to the USGS website.