JOHANNESBURG (Reuters) - Five people have been killed by a gas explosion in an unused coal mine in South Africa's eastern province of Mpumalanga and several others remain trapped, police said on Thursday.
State broadcaster SABC said about 20 people were still stuck underground at the mine in Middleburg.
Rescue efforts were hampered by dangerously high levels of toxic gas underground, SABC said.
The mine is owned by Tegeta Resources and Exploration, which is undergoing creditor protection after its owners, the Gupta brothers, found it difficult to continue doing business in South Africa following corruption allegations against them.
Several people had entered the mine on Wednesday afternoon to steal copper wires that supply electricity for lighting and ventilation when a gas pipe exploded, police spokesman Leonard Hlati said.
"The mine is wired with copper. They were going for copper," Hlati said.
Copper is often stolen from disused mines in South Africa and sold for scrap.
The Gupta brothers, their lawyers and officials from their firms and family representatives could not be reached for comment about the mine incident.
The brothers - who headed what was one of the country's biggest conglomerates - were accused of unduly influencing former president Jacob Zuma over political appointments and winning contracts.
Zuma and the Guptas deny any wrongdoing.
(Reporting by Tiisetso Motsoeneng; Editing by James Macharia; Editing by Dale Hudson)