Two citizens of Russia as well as one from Ukraine and one from Turkey have been charged with hooliganism in an attempt to scale the Prirazlomnaya oil rig in the Pechora Sea, Greenpeace Murmansk staff press secretary Yulia Pronina said.

"We know that hooliganism charges were brought today against Ruslan Yakushev, Andrei Allakhverdov, Yekaterina Zaspa and Gizem Akhan," she told Interfax on Monday.

Pronina added that the piracy charges had not been dropped so far.

Ukrainian citizen Yakushev and Turkish citizen Akhan were the Greenpeace Arctic Sunrise cooks, Russia's Allakhverdov headed the press service and Russia's Zaspa was the ship's doctor.

A regional police source told Interfax earlier that the court started to bring accusations against the Greenpeace activists on Friday and continued to do so on Monday. The source said that various charges might be brought, including piracy.

The Arctic Sunrise vessel of the Greenpeace international nature conservancy organization was detained in the Pechora Sea on September 19 for an attempt to stage a protest against the Prirazlomnaya drilling for oil.

The coast guard escorted the Arctic Sunrise to Murmansk on September 24. It had a multinational crew of 30, including four Russians. All of them were arrested and charged with piracy.

Russian Investigative Committee spokesman Vladimir Markin said on October 22 that the piracy counts had been replaced with hooliganism.