Russian authorities on Wednesday released a Brazilian Greenpeace activist from prison in Saint Petersburg after she was granted bail, the first of 19 arrested campaigners set to leave jail. Ana Paula Maciel, a deckhand on Greenpeace's Arctic Sunrise ship, walked out of jail following two months in detention after she and 18 crewmates were granted bail, the group said. "Ana Paula Maciel has left prison! She is free! The first of the Arctic 30," Greenpeace's Russian office said on Twitter as hearings continued into the 30 activists charged with hooliganism over their protest against oil prospecting. Greenpeace posted a photo of Maciel smiling broadly outside the prison and holding a piece of paper with the handwritten message "Save the Arctic." Maciel was granted bail on Tuesday, prompting Brazilian President Dilma Rousseff to write on Twitter: "I am delighted with the news." The decision to grant bail to prisoners including the U.S. captain of Greenpeace's campaign ship has raised cautious hopes for the activists in a case that has caused global concern. But they still face grave charges that could see them jailed for up to seven years on charges of hooliganism. The latest Arctic Sunrise crewmembers to be granted bail in Saint Petersburg on Wednesday evening were British activist Anthony Perrett and Danish third mate Anne Mie Roer Jensen. Earlier courts in Saint Petersburg -- who were considering whether to extend their detention by another three months -- granted bail to the veteran U.S. captain Peter Willcox and Dutch citizens Faiza Oulahsen and Mannes Ubels, as well as Britain's Alexandra Harris and Kieron Bryan. Willcox is one of Greenpeace's most experienced activists who was also the captain of its Rainbow Warrior ship blown up by the French foreign intelligence service in 1985. Russia had held the 30 crewmembers since September after activists scaled an oil rig in the Barents Sea owned by energy giant Gazprom to protest against oil prospecting. Twelve activists had already been granted bail on Monday and Tuesday but were awaiting release pending the transfer of the bond funds from Greenpeace. The crewmembers' detention caused an international outcry, with stars including Madonna and Paul McCartney and politicians such as German Chancellor Angela Merkel calling for their release. 'I'm going to enjoy fresh air' Oulahsen appeared in court with the slogan "Save the Arctic' written on her palm and hugged a friend through the bars of her cage. In a video released by Greenpeace from the courtroom, she said: "I'm going to enjoy the fact that I can walk more than just three yards in the cell and some fresh air." Greenpeace quoted Harris as saying: "Every day in prison for me is connected with the struggle." Those released by courts in Saint Petersburg are unlikely to immediately be able to go home. They could be placed under house arrest or made to sign undertakings not to leave the city before the trial. Those granted bail remain under arrest until the funds are transferred. Greenpeace has said it will supply the bail payments of 2 million rubles ($61,400) for each activist. Greenpeace International on Wednesday said it has already posted bail for nine of the Arctic 30, but does not expect them to be released before the weekend and cautioned their future status was unclear. "It is still not clear whether their movements will then be restricted. None of them have passports after they were confiscated," Greenpeace said. Of the activists to have so far appeared before the court, only one has been ordered to stay in detention pending trial. A court on Monday ordered Australian activist Colin Russell, 59, who acted as the ship's radio operator, to remain in pre-trial detention until February 24, a day after the end of the Sochi Winter Games. Greenpeace has said it was "baffled" as to why he was being treated more harshly than the others. Australia's ambassador to Moscow Paul Myler said he was going to the Russian foreign ministry Wednesday to seek an explanation.