A leftist, anti-government faction in an Indian town where a Finnish rights observer was killed in April said Thursday its leader has been shot to death along with his wife, authorities said.

Jesus Martinez Flores, the self-styled mayor of the "autonomous" Triqui Indian town of San Juan Copala in southern Oaxaca state, said the leader of the town's autonomy movement was killed Thursday by gunmen from a rival faction.

Flores said Timoteo Alejandro Ramirez and his wife Cleriberta Castro died in the attack.

Neither of the rival factions nor the state government were immediately available to comment on the report. Police rarely enter the remote, rural township because of violent disputes which date back years.

In 2007 some residents of the impoverished town declared autonomy similar to that practiced by the leftist Zapatista rebels in Chiapas. Two other, older Indian groups now oppose the autonomy, which often involves refusing federal and state aid.

On April 27, gunmen ambushed a caravan of rights observers and leftist political activists on their way to the town, killing Finnish human rights worker Jyri Jaakkola and Mexican political activist Beatriz Carino Trujillo.

The deaths remain under investigation.