Three soldiers are among the six who died in an accident involving a gas leak at the Salisbury Island naval base at Durban harbour.

Rescue Care spokesman Garrith Jameson confirmed that three of those died are South African National Defence Force (SANDF) soldiers. It is believed that the three other people who died are part of a team contracted to do work at the base.

It is understood that men had been working in a partially flooded underground shaft or pit inside a disused building at the naval base‚ according to a source with knowledge of the incident.

SANDF spokesperson Mafi Mgobozi said the accident was being investigation.

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“I have people on the ground‚” he said‚ unwilling to be drawn on the death toll or whether any of the dead were members of the military.

When the Times Media team tried to access the scene it was blocked by an armed guard.

An emergency service member‚ who spoke to Times Media on condition of anonymity‚ said a group of workers were reportedly underground when the gas leak occurred.

ER24 spokesman Russel Meiring confirmed the six deaths‚ in what he called a “freak accident“.

“ER24 paramedics arrived on the scene and found rescue teams already in attendance. Rescue teams had already retrieved the bodies of six men from the sewer pit‚” he said.

The injured were transported by private and military ambulances to Durban hospitals.

Earlier in the week‚ one SANDF member died when the flatbed truck transporting a tank was involved in an accident. Then‚ on Wednesday‚ another SANDF member drowned while swimming in the sea off Durban’s main beachfront.