The world’s largest active volcano, Hawaii’s Mauna Loa, has erupted for the first time in almost 40 years, BBC reported.
The lava flow is mostly contained within the summit, but residents have been placed on alert and were earlier warned about the risk of falling ash.
The US Geological Service (USGS) has said the situation could change rapidly.
The volcano’s alert level has also been upgraded from an “advisory” to a “warning” – the highest classification.
No evacuation orders have been issued and populated areas are unlikely to be impacted at this stage, emergency officials say.
Mauna Loa, located inside Hawaii Volcanoes National Park, covers half of the US state’s Big Island. The volcano rises 13,679ft (4,169m) above sea level and spans an area of more than 2,000 sq miles (5,179 sq km).
It erupted at 23:30 local time on Sunday (09:30 GMT Monday) at Moku’āweoweo, the volcano’s summit caldera. Calderas are hollows that form beneath the summit at the end of an eruption.
It followed a series of warnings that an eruption was possible after a spate of recent earthquakes in the region, including more than a dozen reported tremors on Sunday.