At least five workers were killed, two others missing and six injured in a fire at an oil platform in the Gulf of Mexico on Sunday, Mexico's state-owned Petroleos Mexicanos (Pemex), which runs the rig, said Monday.

One of the injured people was in serious condition, Pemex General Director Octavio Romero Oropeza told media at a press conference.

The incident, which happened 100 kilometers from Ciudad del Carmen in the southeast Campeche state, has claimed the lives of a Pemex employee and four workers from Cotemar, a rig maintenance company, he said.

Romero said the company was undergoing an exhaustive search for the missing people, who work for the Conditions and Integrity Monitoring Firm.

Meanwhile, a root cause inspection would be conducted "to determine the source" of the fire "and apply the corresponding insurance," said Romero.

The company said the fire had been brought under control at 4:30 p.m. local time (21:30 GMT) on Sunday, about an hour and a half after it broke out on the Ku-A Process Center's E-Ku A2 platform, which is a part of the Ku-Maloob-Zaap oil field in Campeche Sound.

(Cover: Pemex oil platform  "Ku Maloob Zaap" in the Bay of Campeche, Mexico, April 19, 2013. /Reuters)