Two people died after an excavation site in Barangay Pamplona Dos, Las Piñas City collapsed on Sunday, authorities said on Monday.

The retrieval of the two casualties—who died while digging for the installation of a water pump—was confirmed by FSupt. Sonny Cario, Las Piñas' city fire marshall.

Initial investigation showed that seven workers were at the excavation site along Aquarius Street when the ground caved in at around 2 p.m. Four workers managed to get out of the collapsed pit, while another sustained injuries. Two workers were reported trapped and confirmed dead.

In a radio interview, Las Piñas City Police Assistant Chief of Police for Operations Police Lieutenant Colonel Teoson Rosarito said three other workers survived, with one of them injured and brought to the hospital.

Water concessionaire Maynilad confirmed that the incident occurred at one of its project sites in Pamplona, Las Piñas.

"Maynilad confirms with deep sadness that the two contractor personnel who were trapped following yesterday’s accident at our project site along Aquarius Street, Pamplona Park Subdivision, Brgy. Pamplona Dos, Las Piñas City, have been retrieved and declared dead by authorities," Maynilad said in a statement.

The incident occurred at a construction site for a wastewater pumping facility, which forms part of the Las Piñas Conveyance System Package 2, a wastewater conveyance project.

"We extend our deepest sympathies to their families, friends, and colleagues. We are coordinating closely with our contractor to ensure that the affected families receive immediate assistance and support during this difficult time," the water concessionaire added.

Maynilad said that it is fully cooperating with authorities and is conducting a review with the contractor to determine the circumstances surrounding the incident.

"At this time, our priority is to support the affected families and ensure full cooperation with the ongoing investigation," it said.

Authorities are now conducting an investigation to determine the cause of the collapse.