A group of scientists and nature lovers became trapped while exploring underground tunnels in the Canary Islands, authorities said Sunday. At least two people were dead, they said. The group of 30 - among them scientists from a renowned astrophysics observatory - descended into the tunnels Saturday. Several people appeared to have been struck unconscious by gases, authorities said. The island's emergency services director, Jose Andres Garcia, said the group was in a section about 2 kilometers (1.2 miles) underground in an area where gases may have seeped into the tunnels, robbing them of oxygen. Twenty-three people were rescued. Two bodies were recovered, and four people remained underground Sunday, apparently unconscious, a regional spokesman for the Interior Ministry said by telephone from Tenerife. He spoke on condition of anonymity in accordance with ministry rules.