BANGKOK — Rescue workers searched a large cave network in northern Thailand on Monday in the hopes of finding 12 boys and their soccer coach, who have been missing for two days.

Heavy rains have flooded a narrow passage leading into the cave complex, blocking the group’s exit and complicating rescue efforts, officials said.

The drama of the rescue attempt has dominated television news and social media in Thailand, and King Maha Vajiralongkorn Bodindradebayavarangkun was said to be following the rescue efforts.