* Activists , crew of Greenpeace ship denied bail
* Thirty activists face hearings over protest at oil platform
* Investigators have opened piracy case
* Six arrested in Bulgaria protest against Gazprom's Arctic plans
By Steve Gutterman
MOSCOW, Sept 26 (Reuters) - A Russian court on Thursday ordered seven Greenpeace activists and a photographer held in custody for two months pending further investigation over a protest against offshore Arctic oil drilling, drawing criticism from the environmental group.
The eight men, who had been among 30 people aboard a Greenpeace ship used to stage the protest at the Prirazlomnaya oil platform, were denied bail by a court in the northern city of Murmansk, Greenpeace and Russian media said.
Hearings were expected on Thursday for some of the others who had been aboard the Arctic Sunrise, which was seized by Russian coast guards after two activists tried to scale the rig owned by state-controlled Gazprom on Sept. 18.
"We are deeply concerned by the decision of the judge to refuse bail," Greenpeace Executive Director John Sauven said.
The activists denied bail included the captain of the Arctic Sunrise, U.S. national Pete Willcox, as well as activists and crew members from France, New Zealand, Canada, Poland and Russia as well as a Russian photographer, Greenpeace said.
The federal Investigative Committee has termed the protest an attack and opened a criminal case on suspicion of piracy, which is punishable by up to 15 years in jail. The activists have not been charged.
President Vladimir Putin said on Thursday that the activists from 18 countries were clearly not pirates but had broken international law, suggesting they might end up facing less severe charges.
The spokesman for the federal Investigative Committee said on Thursday that activists ordered held for two months might be released on bail before that period ends if their role is found to have been minor, the Interfax news agency reported.
Greenpeace has said it was the Russian law enforcement authorities who broke the law by boarding the Arctic Sunrise and denied the piracy allegations, saying its activists had conducted a peaceful protest.
"The Russian authorities are trying to scare people who stand up to the oil industry in the Arctic, but this blatant intimidation will not succeed," Greenpeace International executive director Kumi Naidoo said in a statement.
Denis Sinyakov, a photographer who was denied bail, said he had covered the protest as a journalist, Greenpeace said.
The environmental activist group says scientific evidence shows any oil spill from Prirazlomnaya, Russia's first offshore oil platform in the Arctic, would affect more than 3,000 miles (4,800 km) of Russia's coastline.
In Bulgaria, police arrested six Greenpeace activists who blocked a Gazprom gas station to protest its Arctic drilling plans. Four of them had chained themselves to fuel pumps and waved banners that read: "Stop Gazprom, Save the Arctic" and "Gazprom = Arctic destruction".
The Prirazlomnaya rig - a crucial part of Russia's troubled effort to tap oil and gas in the Arctic - is slated to start operating by the end of the year and is expected to reach peak production of 6 million tonnes per year (120,000 barrels per day) in 2019.