The Mexican army has been asked to investigate the killings of six people, including two children and a handicapped adult, whose home soldiers burst into arbitrarily.

The National Human Rights Commission issued the request for the military inquiry in the case of the deadly errors in September 2012 in Tecpan de Galeana, in Guerrero state.

"Twenty armed military staff arrived in two official vehicles, and they violently entered into the home" where a family was celebrating a birthday, a rights commission statement released Monday said.

Four adults and two children were killed after being taken out of the home, piled into military vehicles and driven to the village of El Guayabo "where they were killed by gunfire," the group said, citing witness testimony.

The investigation should be for arbitrary arrests and arbitrary executions, the rights group said.

A national ombudsman said the military acknowledges staff involvement but that among the 20, accounts of events vary greatly.

The soldiers reported that their victims had been hiding in bushes and that they were shot in a purported clash. But the bodies were found in an area that was open and free of bushes and trees, the rights group said.

President Enrique Pena Nieto in December sent bills to Congress on forced disappearances and torture, which became worse after 2006, when the federal government launched a nationwide all-out crackdown on the drug trade.

More than 170,000 people have been killed and more than 28,000 have gone missing since then.