Three of the 30 people arrested during a Greenpeace protest walked free on bail on Thursday, defiant that the action against Arctic oil drilling was justified and that the response by the authorities was not.

Denis Sinyakov, 36, a freelance photographer, caught his wife in a bear hug and Ekaterina Zaspa, 37, the doctor on the Arctic Sunrise icebreaker, was greeted by her husband.

"I am not guilty, and there is no crime in people organising peaceful protests," Sinyakov told reporters outside the court in Russia's second city of St Petersburg.

Andrey Allakhverdov, 50, a spokesman for Greenpeace Russia, said he had "absolutely no regrets" over taking part in the protest when activists tried to scale the Prirazlomnaya oil platform operated by state-owned Gazprom in the Pechora Sea.

He joked that the first thing he wanted to do now was to have a shower.

Greenpeace said in a statement that it was not clear how much their movement would be restricted and whether they would be allowed to leave Russia. Russian courts have set bail at 2 million roubles ($61,100) for each of the so-called "Arctic 30".

All those onboard the Arctic Sunrise icebreaker face seven-year jail terms on hooliganism charges.

Twenty four of those detained on Sept. 18 have been granted bail this week following criticism of President Vladimir Putin over what was widely seen in the West as their harsh treatment, though only four have been freed so far.

Brazilian Ana Paula Alminhana Maciel was the first to be released on bail on Wednesday, brandishing a sheet of paper with the words "Free the Arctic" written on it.

Western leaders and celebrities have expressed concern over detention for the activists from 18 countries, and the release of some marks an easing in Russia's treatment of the 30, who initially faced 15-year jail terms under piracy charges.

A Russian court also granted bail to Greenpeace activists Jonathan David Beauchamp of New Zealand, Ruslan Yakushev of Ukraine, Briton Frank Hewetson and Alexandre Paul of Canada on Thursday.

The Kremlin may believe freeing them under bail could ease criticism of Russia, which hosts the Winter Olympics in February. Putin has said they are not pirates but that they did violate the law.

The investigation is ongoing and no trial date has been set. Custody hearings for the other detainees are continuing.

Greenpeace, which says its protest was peaceful and the charges of hooliganism are unfounded, is concerned drilling for oil in the Arctic threatens the region's pristine environment.

Putin has said that development and shipping there are important to Russia's economy and security.