(Updates casualty count)
Twenty-six workers were killed Tuesday in a explosion and subsequent fire at gas plant in the northeastern Mexican state of Tamaulipas, state-owned Petroleos Mexicanos said.
A company spokesperson told Efe that 27 people had been injured in the blast and fire.
The explosion occurred around 10:45 a.m. at the facility near Reynosa, a city just across the border from McAllen, Texas, Pemex said in a statement.
It took nearly two hours to put out the ensuing fire.
"Specialized technicians with Pemex Exploration and Production will proceed to carry out the analysis of the root cause of the accident, as well as the evaluation of the damage caused to the installation," the state oil monopoly said.
Pemex boss Juan Jose Suarez Coppel was expected to arrive in Reynosa by Tuesday evening, company sources told Efe.
Tamaulipas authorities temporarily evacuated residents living within a 5-kilometer (3-mile) radius of the plant, but there were no reports of injuries to anyone outside the Pemex facility.
At least 700 people were working at the time of the blast, a Pemex employee said while being treated by paramedics, who were attending to a dozen people with serious injuries.
Soldiers, firefighters and state workers supported the efforts of Pemex crews to bring the blaze under control.
Tuesday's explosion was Pemex's worst accident since Oct. 23, 2007, when 22 workers died on an offshore oil platform in the Gulf of Mexico. EFE