Guests at the nearby luxury Blue Lagoon geothermal spa resort were evacuated as a precaution. View on euronews

Volcanic activity on southwestern Iceland's Reykjanes Peninsula is declining, prompting civil protection authorities to lower the alert level from "emergency" to "threat," Icelandic public broadcaster RUV reported Thursday.

A large sulfur dioxide gas cloud is blowing toward Keflavík International Airport. Authorities have told people nearby to stay indoors and keep their windows shut as pollution levels rise. Despite this, flights are running normally and the airport remains open.