A Greenpeace ship impounded by Spain earlier this month as it protested oil exploration off the Canary Islands was allowed to leave on Wednesday after payment of a 50,000-euro bail, the group said.

The Arctic Sunrise "left at 5:00 pm local time (1700 GMT) and set off toward Valencia" in eastern Spain, a spokesman for the environmental group said.

Spain said it impounded the ship because the crew defied orders to leave a restricted zone where they were protesting against oil exploration off the Canary Islands.

On November 15, three Spanish navy boats rammed vessels in which Greenpeace activists were approaching a ship belonging to Spanish energy firm Repsol, video distributed by Greenpeace showed.

An Italian protester fell in the water and was injured, Greenpeace said. It said its activists were protesting peacefully.

Authorities impounded the boat on November 18 at the port of Arrecife on the island of Lanzarote.

Greenpeace had said the captain, a US national, was being refused release until the 50,000-euro ($63,000) bond was paid. It had initially refused to pay.

The organisation has filed an appeal and says it plans to pursue a case against the "disproportionate" response by the navy.

The beaches of the Canary Islands, an Atlantic archipelago off northwest Africa, are a popular draw for tourists from Britain, France and elsewhere.

This month's incident was the latest involving the Arctic Sunrise, which was seized by Russian commandoes in September 2013 during a protest against Arctic oil drilling.