Mexico's governmental human rights commission says it condemns violent incidents like a shootout between federal police and suspected criminals that left 42 suspects and one policeman dead.

The rights commission said Tuesday it has opened a formal investigation into last week's shootout at a ranch in western Michoacan state because of "the seriousness and importance of the allegations."

The commission did not describe the allegations, but newspaper columnists and observers have raised doubts about the lopsided death toll.

In 2014, an investigation by the commission found soldiers executed suspects in a separate incident at a warehouse in neighboring Mexico state in a similarly lopsided confrontation.

The commission said it was also investigating the deaths of nine civilians during a January protest and confrontation with police in another part of Michoacan.