Four people were injured in an explosion at a power plant in the eastern Mexican state of Hidalgo on Monday, state-owned utility CFE said.

"The injured were taken immediately for medical attention, and it is reported that they are stable and out of danger," said the company in a statement.

The incident, the statement went on to say, occurred at around 10 a.m. "in the area of the Unit 5 burners of the Francisco Perez Rios Thermoelectric Center" in the municipality of Tula.

Authorities say they do not yet know what caused the blast.

The injured were ICMOSA contracting firm workers who were in the area at the time of the explosion.

"The incident caused no effect on the operation of the plant, which is reporting nothing new and operating normally," CFE said.

The company, the statement added, "has tasked the Electrical Investigations Institute with performing the relevant tests to determine the causes" of the explosion. EFE