Eight Mexican soldiers sustained injuries in an explosion at a military barracks in the western state of Michoacan, authorities said.

Previous reports from emergency management officials had indicated that 17 people were injured in Friday's blast, although the Defense Secretariat subsequently lowered that number to eight, saying in a statement that the troops had suffered only "superficial injuries."

The accident occurred at a barracks in the city of Zamora when soldiers were preparing to destroy fireworks that had previously been confiscated.

The injured were taken to a military hospital in the neighboring state of Guanajuato and their condition was described as stable, the secretariat said, adding that an investigation has been launched to determine the cause of the blast.

Zamora is far from the crime-ridden Tierra Caliente region, which straddles Michoacan, Guerrero and Mexico states.

Vigilante groups sprang up in Tierra Caliente to protect their communities from the Los Caballeros Templarios (Knights Templar) drug cartel and fill a security vacuum that had existed in Michoacan until the recent deployment of federal forces. EFE