Israeli police arrested 17 Greenpeace activists on Thursday after a group of them infiltrated an Israeli power station by sea to protest the use of coal to fuel power plants, the environmental organization said.

The activists approached the power station at the Hadera power plant in inflatable dinghies and climbed up ropes to reach an elevated seaside coal dock, Greenpeace said.

Then they climbed a massive crane and unfurled a huge, Hebrew-language banner reading "Coal Kills," said Greenpeace spokeswoman Hila Krupsky. She said the protest held up coal deliveries.

Israeli police said six of the activists were arrested on the coal dock.

Greenpeace said nine more activists were arrested after their "Rainbow Warrior" boat reached the Haifa port in northern Israel for inspection by Israeli authorities.

Earlier this month, Israel arrested three Greenpeace activists who sneaked onto an Israel-bound coal ship on the high seas to protest the country's plans to build a new coal-fueled power plant in southern Israel.