WASECA (AP) - Two teenagers facing explosives-related charges in connection with a foiled plot to attack a southern Minnesota school have pleaded guilty.

Both teens pleaded guilty late last week to felony possession of explosive material. They were accused of helping a classmate detonate several small "test bombs" around Waseca, resulting in property damage.

Their classmate is accused of plotting to kill his family and attack his school with firearms and homemade explosives. Police and prosecutors don't believe the two teens were aware of the plot.

Waseca County Attorney Brenda Miller said she was pleased with the plea agreement.

The teens will be on a form of probation and must perform community service and must write letters of apology.

All three were 17 when they were charged. The Associated Press generally doesn't identify juveniles accused of crimes.