An explosion and fire killed at least 26 people at a Pemex natural gas facility in northern Mexico near the U.S. border on Tuesday, Sept 18, one of the deadliest accidents in the oil and gas industry in recent years, Reuters reported.

Television footage showed flames leaping high into the sky during the blaze at a gas compression station near the city of Reynosa, a key entry point for natural gas to Mexico from the United States.

It was the third blaze in about five weeks at state-run oil monopoly Pemex installations in Tamaulipas, a border state that has struggled to contain the menace of warring drug gangs. Pemex's top executive said the fire appeared to be an accident.

Parts of the plant were reduced to a mangled wreckage of twisted, charred tubing, the earth beneath scorched black. Soldiers stood guard with assault rifles at the entrance.

Pemex said gas imports from the United States were not affected, as the station stores gas from Mexico's Burgos field, and is not an import terminal.

The cause of the fire was unclear. Pemex said it was still investigating after fire fighters brought it under control on Tuesday afternoon.

"There is no evidence that the explosion was provoked, but rather that it was an accident," Pemex CEO Juan Jose Suarez Coppel told reporters after touring the site.

Illegal tapping of pipelines, often by criminal gangs, has cost Mexico hundreds of millions of dollars and sparked other major fires in the past.

Four of those killed on Tuesday were Pemex staff, and the other 22 were contract workers, the company said. Seven workers were still missing, while 28 people were hospitalized, two in serious condition, Pemex said.