MEXICO CITY – The Mexican government said Thursday that two missing members of a small rebel group were the victims of a “forced disappearance” and not a kidnapping, indicating the government may have been involved.

The leftist People's Revolutionary Army, or EPR, has long claimed Edmundo Reyes Amaya and Raymundo Rivera Bravo were taken by security forces in the southern state of Oaxaca, but the government until now has said the men were likely kidnapped.

Officials from the Interior Department did not immediately respond to a request asking for an explanation of what they meant by “forced disappearance.”

The 1992 United Nations' definition of “forced disappearance” is that government officials were responsible for the kidnapping of someone.

The men's disappearance prompted a spate of gas pipeline bombings in 2007 by the EPR, which pledged to carry out more attacks if the men were not released.

The Interior Department said in a news release Thursday that the Attorney General's Office is in charge of the probe and the men's relatives will have access to the case files.

Members of the Mediation Commission, overseeing talks between the government and the EPR, cheered the announcement, but said they would like to see concrete actions to show the government's commitment to a thorough investigation.

“We welcome the unexpected change recognizing that this is a case of forced disappearance and not just a kidnapping,” said Carlos Montemayor, the commission's spokesman.

It was not possible to get comment from the EPR.