JAKARTA: More than a dozen patients and staff are trapped beneath the rubble of a hospital that was flattened when a 6.2-magnitude earthquake rocked Indonesia's Sulawesi island, killing at least three people, authorities said.

"The hospital is flattened -- it collapsed," said Arianto from the rescue agency in Mamuju city, who goes by one name.

"There are patients and hospital employees trapped under the rubble and we're now trying to reach them," he added, without giving a specific figure.