Backup to aid the security officers arrived, including a federal police helicopter, at which point the gunmen spread throughout the property, Rubido said.
The confrontation stretched for hours because of the size of the property, Rubido said. There were at least three standoffs in different parts of the property, he said.
This was a slightly different version than what the mayor of Tanhuato said in an earlier interview. According to the mayor, there were two different shootouts in different locations.
The death toll was 42 gunmen and one federal police officer, who was shot while providing aid to an injured colleague, Rubido said.
The three gunmen who were arrested have been turned over to state prosecutors, he said.
In addition, the security forces seized eight vehicles, six were inside the warehouse and were burned when the structure caught on fire, the commissioner said.
A photo of the burned-out vehicles had been shared earlier on Twitter by a group of citizens who monitor violence in Michoacan.