Human Rights Watch says evidence in two recent shootings in Mexico suggests federal police killed protesting civilians and criminal suspects who were fleeing or had surrendered.

The New York-based organization is the second international group to call on the Mexican government to clarify the events of Jan. 6 in Apatzingan and May 22 in Tanhuato, both in the western state of Michoacan.

A combined total of 50 people were killed in the two confrontations that caused barely any police casualties.

In Tanhuato, 42 suspected criminals died in an alleged shootout and only one federal police officer was killed. In Apatzingan, eight civilians were shot dead in the street, some huddled together beneath an SUV for protection.

The rights group cited witness statements in its report released Wednesday.