MEXICO CITY (AP) — Armed assailants killed Mexican lawyer and indigenous rights activist Patricia Rivera Reyes, authorities announced Monday.

The prosecutors' office in the northern border state of Baja California said three masked intruders burst into a home in the border city of Tijuana where a festivity was being held Saturday night.

The intruders robbed party-goers of their personal possessions. Rivera Reyes reportedly demanded her cell phone back, when one of the assailants shot her in the head.

Another man at the house was also shot in the head and taken to a local hospital.

Early this year, the government acknowledged that 97 community and rights activists have been killed during the current administration, which took office Dec. 1, 2018. Officials said 90 percent of those crimes have yet to result in convictions.

So far this year, eight journalists have been murdered in Mexico.

The Indigenous groups in northern Mexico are smaller and less well known than those in the south. Some of the groups live on both sides of the border.

They have suffered centuries of oppression and seizure of their traditional lands.