RIO DE JANEIRO (AP) — A seven-story building collapsed Tuesday in the Brazilian city of Fortaleza, killing at least one person and leaving others trapped under the debris, officials said.

Authorities in the city of 2.6 million inhabitants in the country's northeast said some of the people trapped are communicating with relatives and rescuers by cellphone.

"There are accounts on 10 to 15 people still inside the building, but we cannot speculate. We cannot make any estimates on how many people are inside at this moment," said Lt. Romario Fernandes, a spokesman for the local fire department. He said three survivors had been taken to hospitals.

Fernandes told TV channel GloboNews there were at least three apartments per story in the collapsed building located in an upscale area of central Fortaleza.

"For now we are trying to hear sounds that indicate where people are. There are several layers of debris," he said, adding that the rescue operation is expected to last days.

Neighbor Daiane Moreira was working next to the building when the incident took place.

"I just heard a boom and the building collapsed at once. A man came drenched in blood and with a broken arm, he was the only one we could help," Moreira told journalists at the scene, as relatives and friends of building residents wept and waited for information.