Updated

An armed gang freed more than 50 inmates from a prison in central Mexico on Saturday — including two dozen with ties to a powerful drug cartel — in a daring raid that took just five minutes, a state governor said.

The prison director, 40 guards and two police commanders who were on duty at the Cieneguillas prison in Zacatecas state were detained for questioning, according to Gov. Amalia Garcia Medina. She said footage from the security cameras inside and outside the prison indicates that guards helped the armed gang, although she did not provide details.

"It's clear to us that it was a perfectly planned operation with inside help because it lasted just five minutes and not one shot was fired," Garcia said at a news conference.

About 20 gunmen arrived at the prison before dawn in 10 vehicles and freed 53 prisoners, including at least 27 with ties to the Gulf cartel, she said.

She said the jailbreak may have been revenge for the recent arrests of drug gang members and the seizure of guns and narcotics by the Zacatecas state police.

"This will not go unpunished," she said. "The investigations will be conducted with the full weight of the law to their last consequences."

She said the army and federal police were on a manhunt for the fugitives.

Corruption among police and other government officials has been a key obstacle in Mexico's U.S.-backed efforts to root out ruthless drug cartels.

President Felipe Calderon has acknowledged that corruption permeates all levels of Mexican police. He has sent more than 45,000 soldiers to combat drug gangs, although the army has also been accused of abuses in the offensive.

Drug violence has become increasingly brutal as rival gangs fight each other for territory and stage bold attacks against police.

The bodies of two men were found shot to death in central Michoacan state early Saturday, police said.

One of the men was thrown out of a car in front of a pizzeria at a plaza in the city of Patzcuaro. He had been blindfolded, shot in the head and had his hands tied. A sign had been taped to his back reading "Rufos, we are the resistance against you and the Z," an apparent reference to the Zetas, a group of Gulf cartel hit men.

Drug violence has killed more than 10,750 in the last 2 1/2 years.

Mexico has arrested at least 327 cartel members since Calderon took office, but the highest-ranking leaders remain at large.