SAN JUAN, Puerto Rico (AP) — Authorities in the eastern Caribbean island of St. Vincent said Wednesday they believe an active volcano is in danger of exploding and have ordered mandatory evacuations.

The island’s emergency management office switched the alert level to red and said the first cruise line will arrive after nightfall to evacuate those who live near the La Soufriere volcano. It was not immediately clear how many people would be evacuated, where the ship would take them or if they would remain temporarily aboard.

Evacuation efforts could be hampered by the pandemic.

Prime Minister Ralph Gonsalves said in a press conference that people have to be vaccinated if they go aboard a cruise ship or are granted temporary refuge in other nearby islands.

Gonsalves said he was talking to other Caribbean governments to accept people’s ID cards if they don’t have a passport.

“This is an emergency situation, and everybody understands that,” he said.

Gonsalves added that he highly recommends those who opt to go to a shelter in St. Vincent and the Grenadines, an island chain of more than 100,000 people, be vaccinated.

Officials said the dome of the volcano located on the island’s northern region could be seen glowing by nightfall. The alert issued Wednesday evening follows days of seismic activity around La Soufriere.

The volcano last erupted in 1979, and a previous eruption in 1902 killed some 1,600 people.