KEY WEST, FLA., AUG. 11 -- Two badly battered dolphin activists said they were run over by Navy boats as they swam in the Gulf of Mexico in a futile attempt to stop Navy tests of a secret weapons system.

Former Flipper trainer Richard O'Barry, who successfully blocked the Navy's blast Thursday by sitting on a buoy over a 1,200-pound underwater bomb, suffered a concussion and multiple bruises, according to a medical report from Florida Keys Memorial Hospital.

Animal rights activist Russ Rector suffered a back injury and bruises to the hip and shoulder. He left the hospital with an arm in a sling.

Rector, 42, said he and O'Barry were being propelled through the water by a hand-held motor inside a Navy testing site near the Dry Tortugas at about noon Friday when a boat about 60 feet long ran over them. Five other boats then repeatedly ran over Rector and O'Barry, Rector said from the hospital emergency room. They later learned the test had taken place an hour before.

Navy accounts differ.

A Navy spokeswoman in Key West said the boats did not run over the men. "They, in fact, were trying to get in the way of the boats," said Ensign Robin Perkins.

Dan Probert, who oversees Navy trials of the weapons system, said a Navy boat may have run over the men, but he said he had no details. "Apparently they were pursued, and one of the boats could have hit them," Probert said.

O'Barry had demanded cancellation of the tests because of dolphin sightings in the area.