ANTIGO, Wis. — An 18-year-old man opened fire with a high-powered rifle outside a high school prom in northern Wisconsin, wounding two students before a police officer who was in the parking lot fatally shot him, authorities said Sunday.

Investigators did not say whether they believe the two students were specifically targeted or discuss a possible motive for the shooting Saturday night. But a school administrator said it appeared that the gunman — identified by police as Jakob E. Wagner — intended to go into the dance and start shooting randomly.

The school district said the ‘‘quick actions’’ taken by police and district staff to secure the building ‘‘prevented what might have otherwise been a disaster of unimaginable proportions.’’

In Kansas, authorities found a body in a hotel room that erupted in flames during a shootout in which three federal agents were injured while trying to arrest a robbery suspect, the FBI said Sunday.

The FBI said two deputy US marshals and an FBI agent who were part of a US Marshals Service fugitive task force, suffered nonlethal injuries Saturday night when they came under fire while trying to arrest 28-year-old Orlando J. Collins at a Topeka hotel.

In Arizona, two police officers are in stable condition and a trespassing suspect is dead after a shooting Saturday at a Wal-Mart in a Phoenix suburb, authorities said.

ASSOCIATED PRESS