Baku, July 6, AZERTAC OPEC's Secretary General Mohammad Barkindo has died at the age of 63, Mele Kyari, the chief executive of Nigerian National Petroleum Corporation (NNPC) said Wednesday, according to DW. "We lost our esteemed Dr. Mohammad Sanusi Barkindo," Kyari said on Twitter."Certainly a great loss to his immediate family, the NNPC, our country Nigeria, the OPEC and the global energy community," he wrote. "Burial arrangements will be announced shortly."