Authorities on the Caribbean island of St Vincent believe an active volcano is in danger of erupting and have ordered mandatory evacuations.
The island's emergency management office switched the alert level to red and said a Royal Caribbean cruise ship would arrive after nightfall to take those who lived near La Soufriere volcano.
Others will be taken to shelters elsewhere in St Vincent that are outside the danger zone.
Roughly 16,000 people lived in the red zone and would need to be moved, Erouscilla Joseph, director of the University of the West Indies' Seismic Research Center, told the Associated Press.
Scientists alerted the government about a possible eruption after noting a specific type of seismic activity early on Thursday that indicated "magma was on the move close to the surface", Joseph said.
"Things are escalating pretty quickly," she said of the volcanic activity, adding it was impossible to provide an exact forecast of what might happen in the next few hours or days.
Government officials tweeted that the dome of the volcano on the island's northern region could be seen glowing by nightfall. The alert issued on Wednesday evening follows days of seismic activity around La Soufriere.
The volcano last erupted in 1979 and an eruption in 1902 killed about 1600 people.