MEXICO CITY – Mexican federal officials say they are investigating a tainted batch of an anti-clotting medication given to dialysis patients at a hospital run by the state-owned oil company that has so far resulted in two deaths.

President Andrés Manuel López Obrador, who is from Tabasco state where the hospital is located, said Wednesday he would ask federal health officials to address the situation and he called the deaths “very unfortunate.”

The Petroleos Mexicanos hospital in Villahermosa is monitoring 52 patients who received the tainted medication, including five who remain in intensive care and 30 hospitalized in stable condition, according to a statement this week from Pemex Wednesday night. Six patients have been moved to a specialized hospital in Mexico City.

The company said federal investigations had been opened into both deaths to determine who was responsible.

More than 60 dialysis patients at the Pemex Regional Hospital last week received the heparin sodium medication that later tested positive for the bacteria Klebsiella spp, according to Pemex.

Pemex operates its own healthcare system, including hospitals, for employees, retirees and their families. The gulf coast state of Tabasco is one of its primary centres of operations.