TUXTLA GUTIERREZ, Mexico (AP) _ The governor of Chiapas, beset by rebel calls for his resignation, ended two months in office Tuesday by stepping down and asking Zapatista insurgents to end their fighting.

Gov. Eduardo Robledo Rincon also called for Bishop Samuel Ruiz, who has been accused of collaborating with the rebels, to stop. Neither the Zapatistas nor the bishop immediately responded.

The Chiapas legislature approved his request to leave office and named a federal congressman, Julio Cesar Ruiz Ferro, as interim governor.

The significance of Robledo's decision depends on rebel response, which because of the remoteness of the Chiapas region could take days to become known. It was uncertain if his action would appease the rebels, who also want land reform and a withdrawal of army troops.

The Zapatista National Liberation Army has demanded the resignation of Robledo, who they said was elected fraudulently. Robledo offered at his December inaugural to step down if the rebels disarm.

Election observers said they saw some voting irregularities but found no evidence of widespread fraud.

Robledo's opponents contend Amado Avendano of the leftist Democratic Revolutionary Party won the Aug. 21 election. They swore him in as the head of an ``alternative government'' in December.

Avendano, a lawyer and newspaper publisher from San Cristobal de las Casas, said Tuesday that Robledo's departure ``helps relax the terrible climate of tension in Chiapas.''

``But it is only one of the conditions,'' Avendano said. ``We need peace in Chiapas, but we won't have peace until the soldiers go back to their barracks.''

The national government maintains Robledo's status is a local affair. However, several governors were forced out by former President Carlos Salinas de Gortari.

Robledo said he acted independently. ``Now it is up to the rest to contribute to the re-establishment of peace and social order in Chiapas,'' he said.

President Ernesto Zedillo asked the rebel leader, Subcomandante Marcos, to clarify his intent to find a peaceful solution. Zedillo said he would order the army to avoid confrontation with the rebels.

The Zapatistas began fighting in Chiapas on Jan. 1, 1994, demanding rights and services for the region's impoverished Indians. More than 145 people were killed before a cease-fire 12 days later.

Under pressure from the military and investors to resolve the conflict in Chiapas, Zedillo's government authorized a major army push into the rebels' territory on Thursday.

The army offensive worries human rights groups.

``New incursions by the Mexican army into the southern state of Chiapas could renew armed conflict and give rise to torture and other gross human rights violation,'' the London-based Amnesty International cautioned Tuesday.

In a communique this week, the Zapatistas accused the government of conducting a ``dirty and genocidal war.''

``We painfully denounce ... the barbarities and the dirty war and genocide that the federal government headed by Zedillo has committed,'' a rebel communique said Monday. ``Federal troops, along with the police, are detaining and torturing civilians ... including women and children.''