The tour group that organised Sunday’s visit to the Breidamerkurjokull glacier, in southeast Iceland, initially reported that 25 people were in the group, but on Monday amended the number to 23.

Sudurland police said in a statement on Facebook that there had been “conflicting information about the number of people on the trip,” and the search had continued as a precaution to ensure that no one was trapped.

The tour group was on an organised visit of the glacier with a guide when the cave collapsed, police said.

An American man was pronounced dead at the scene, police said, and an American woman – whom media reports said was the deceased’s fiancee – was injured and in “stable” condition in hospital.

More than 200 people took part in the search in “difficult” conditions for those believed missing, police said, moving big blocks of ice by hand.

The glacier where the accident happened is near the Jokulsarlon glacial lagoon, one of Iceland’s most popular tourist destinations.