Mexico's defense secretary says the country's army isn't happy doing law enforcement duty, but has no other choice.

The statement by Gen. Salvador Cienfuegos comes after soldiers have been implicated in rights abuses.

Cienfuegos told local media in an interview broadcast Thursday that "none of us got into the armed forces to do this," referring to the military's role in fighting drug cartels and other criminals. But he added: "If the armed forces don't do it, there is no one else to do it."

Cienfuegos said "we are not comfortable, we didn't ask for this, we didn't study for this, but apart from obeying the president's order, society is asking us to do this."

Local police forces in Mexico are often too week or corrupt to take on the cartels.