Rescuers have recovered the bodies of all seven workers trapped in a collapsed mine in northern Mexico, President Andres Manuel Lopez Obrador said Friday, ending any hope of finding survivors.

The workers were buried a week ago in the accident in the country's main coal-mining region in Coahuila state.

"We send our condolences to the families," Lopez Obrador told reporters as he announced the retrieval of the last bodies.

According to preliminary investigations, the mine flooded after a dam ruptured.

Investigators are seeking to determine "if the collapsed mine was safe," Lopez Obrador said.

Coahuila has seen a series of fatal mining accidents over the years.

The worst was a gas explosion that claimed 65 lives at the Pasta de Conchos mine in 2006.

The bodies of 63 miners remain at the site. The families have repeatedly appealed to the Mexican authorities to recover them.

Last September, Lopez Obrador promised the remains would be retrieved.