Russian authorities on Thursday dropped criminal charges against the last of 30 Greenpeace ship crewmembers who spent two months behind bars after a rig-scaling protest against oil drilling in the Arctic, a spokesperson for the environmental watchdog told Efe.

Italy's Cristian D'Alessandro was the last of 30 people on board the Arctic Sunrise icebreaker - 28 Greenpeace activists and two freelance journalists covering their protest - to benefit from an amnesty bill passed earlier this month by Russia's parliament.

The non-Russian crew members, all but four of the 30, will now be able to leave the country once they receive their exit visas.

The "Arctic 30" spent two months in pre-trial detention in the cities of Murmansk and St. Petersburg after being arrested on Sept. 19, a day after some of the activists tried to scale the Prirazlomnaya oil platform - operated by Russian state energy giant Gazprom - in the Barents Sea.

The activists and journalists had been released on bond in late November after the charges against them were downgraded from piracy, punishable by up to 15 years in prison, to hooliganism, which carries a maximum prison term of seven years.

The Greenpeace spokesperson said British activist Anthony Perrett received his exit visa on Thursday and could return home at any time.

Greenpeace still insists that the Russian courts declare as illegal the arrest and attempts to prosecute the "Arctic 30" and also wants to recover the Arctic Sunrise, which is being held at the port of Murmansk. EFE