Whakaari/White Island, New Zealand's most active cone volcano, erupted on Monday, injuring as many as 20 people, authorities said.
The volcano is in the Bay of Plenty, and the island is a popular tourist attraction. Prime Minister Jacinda Ardern said it is believed that "100 people were on or around the island" when the volcano erupted, and some are unaccounted for. The government does not yet know if there have been any deaths.
Radio New Zealand said there are five helicopters, an ambulance crew, and a mobile triage unit on the way to the island, which is about 30 miles off the northeast coast of New Zealand.