Authorities in Mexico say the military has rescued 20 people who were being held for ransom in a house in the northern city of Monterrey.

Officials Sunday said the men were found with their hands and feet tied, and were being held for ransoms ranging from nearly $2,000 to about $4,300.

Monterrey has been the scene of deadly battles involving drug cartels fighting over routes into the United States.

More than 37,000 people have been killed in drug-related violence since President Felipe Calderon took office in late 2006 and began cracking down on the nation's cartels.