SAN CRISOTBAL DE LAS CASAS, Mexico (AP) _ Eight Spanish volunteers have filed charges of illegal imprisonment and harassment against Mexican police who detained them last week in the southern state of Chiapas.

Foreign and Mexican volunteers have been harassed by Mexican authorities since Indians here began their rebellion nearly three years ago, but Monday's charges were the first time a formal complaint has been filed.

The Spaniards and three Mexicans were detained Friday as they returned from supervising workshops on literacy and legal rights for women in the village of Jardin, about 25 miles north of here.

``It was the first time in my life I've seen so many guns pointed at me,'' said a shaken Marta Inmaculada Chine Labrador, 19, of Fraga, Spain. ``I didn't understand anything. We didn't know where they were taking us.''

They were were released Saturday after immigration authorities interrogated them about suspected political activities.

The region around the village is not considered part of the conflict zone here rebels of the Zapatista National Liberation Army and federal troops have been at a standoff since January 1994 when at least 145 people were killed in 12 days of fighting.

The volunteers said they were forced into a police truck and driven around the nearby town of Simojovel, along with the bodies of four people who had been murdered in an apparently unrelated incident earlier last week.

The two Mexican women with the group, Rocio Diaz Arroyo, 20, and Matea Jimenez Lopez, 21, said police threatened to rape them.

``They started to decide which ones we would go with and made obscene gestures,'' Diaz said, weeping.

The volunteers said they were taken to a series of jails and were not allowed to make telephone calls. They said they received no medical attention, although two people were ill, one with typhoid fever.

Authorities substituted their tourist visas for letters saying they were voluntarily leaving the country _ a method frequently used to eject unwanted foreigners that falls short of deportation.

State officials were not immediately available for comment.