Greenpeace says Spain's navy has rammed into its dinghies during a protest in the Atlantic Ocean against oil exploration near the Canary Islands, seriously injuring one of the environmental organization's activists.

The navy, which took the injured protester to a hospital by helicopter, said she was hurt Saturday by propellers from a Greenpeace dinghy.

Joel Stewart, captain of Greenpeace ship Rainbow Warrior, told The Associated Press that the 23-year-old Italian activist was hurt when a navy boat slammed into her inflatable dinghy during the peaceful protest.

On Oct. 24, the Spanish government asked the Constitutional Court to block proposals by the Canary Islands regional government to hold a referendum on oil exploration in waters off the popular tourist archipelago.

The government has licensed Repsol S.A. to begin oil exploration there.