A ten-story hotel collapsed in the Buenos Aires Province coastal town of Villa Gesell in the early hours of Tuesday. An elderly man’s body was recovered from the debris, and a woman has been found alive and taken to hospital. The exact toll of the accident is unknown, but authorities estimate seven to nine people are still missing.

In addition to the hotel, an adjacent building suffered extensive damage. Aerial photos show that the building was virtually cut in half.

The people staying at the Dubrovnik Hotel are believed to be builders who had been hired for informal construction work at the back of the building, where the collapse began, according to a press release on the Villa Gesell municipality website. The construction work had not been authorized by the local authorities and did not meet municipal guidelines.

The municipality had detected the works were being done and ordered the owners to stop them in August. However, they continued to carry out other authorized works, the release added.

The owner of the hotel, her nephew, and another woman may be among those trapped under the debris, a former hotel worker and friend of the owner told TV channel C5N.

“She is trapped in there,” she said of the owner, visibly moved. “I worked for her, she is my friend.” She said that the owner lived in the hotel with her nephew and one of her former co-workers. 

Although the exact reason for the collapse is still unknown, the structure at the back of the building was being modified “illegally and irregularly,” the municipality said.

Four construction workers have been arrested on suspicion that they may hold responsibility for the incident, Buenos Aires Province Security Minister, Javier Alonso, told the press. “Apparently, two of them were in the hotel and the other two went there when they heard about the collapse,” Alonso said. Two architects are also under investigation.

The prosecutor’s office also ordered the federal police firefighters department to establish the cause of the collapse.

Villa Gesell is a popular beach destination, especially for young people, around 400 kilometers from Buenos Aires City. It is currently spring in Argentina, and the tourist destination is in low season, so the hotel was therefore closed, occupied only by the builders.

Around 300 police officers, firefighters and personnel from local and nearby municipal offices were working at the site of the tragedy, removing debris by hand.

According to Villa Gesell Mayor Gustavo Barrera, the rescued woman “was lucid despite being pretty roughed up.”

“This is a very complex situation, we have never experienced anything like this,” he told the press.

Security Minister Patricia Bullrich announced on Tuesday morning that she would send federal police teams for aid, including structural engineers, rescue experts, rescue dogs and police officers for logistical and operational support.