ST. PAUL — St. Paul authorities are again warning people to stay away from the city’s caves by the Mississippi River.

Crews were called to rescue two teenagers who were seen entering a hole leading to the caves Friday afternoon. St. Paul Assistant Fire Chief Mike Gaede said the teens emerged by themselves and were not hurt.

The teens entered a hole the city already had planned to close Saturday.

The cave system has posed a danger for curious explorers for decades.

Gaede said the caves are not safe, and it’s illegal to be in them.

Three teenagers died from carbon-monoxide poisoning after entering the caves in 2004.