ARKHANGELSK, September 18 (Itar-Tass) - Activists of Greenpeace have failed to gain footing on the Prirazlomnaya oil platform of Russian gas giant Gazprom in southeastern waters of the Barents Sea, northwest Russia.

Coordinator Yevgeniya Belikova told Itar-Tass on Wednesday that six Greenpeace activists boarded boats from the Green movement icebreaker Arctic Sunrise at 00:30 GMT aiming to mount the oil platform and unroll banners demanding a stop to Arctic oil drilling.

However, she said, “Two of them, Marco Polo and Sini Saarela, were detained by Russian border guards. We are unaware whether they are arrested or not." A report that Finnish alpinist Saarela had broken her hand was not confirmed.

No Greenpeace activists were on the platform, Belikova added, noting that the icebreaker was anchored not far away and that talks were proceeding with those aboard a Russian border patrol vessel. “Russian border guards are going to get onboard the icebreaker for an inspection,” Greenpeace Russia said.

Border guards fired warning shots at Arctic Sunrise,  Yevgeniya Belikova added. She claimed that when the activists tried to mount the platform the border guards threatened them with firearms and with possible shooting at the vessel in case they didn't quit the territory.

Prirazlomnaya is installed on the shelf of the Pechora Sea and is preparing to launch operations. It was built at the Sevmash military shipyard in northern Russia's Severodvinsk. The platform can operate in extreme climatic conditions amid icepack and an air temperature of minus 50 degrees Celsius. Tanks on the platform can carry 110,000 cubic meters of oil.

It is expected to reach the maximum production volume in seven years' time. The oil shelf where the platform operates,called "Prilazlomnaya," has an estimated oil reserve of 72 million tons.

Some 200 workers will drill up to 40 wells to produce, store and load crude aboard tankers year-round. Extractable reserves of the Prirazlomny oil field are estimated at 72 million tons. The permanent ice-resistant platform should reach full capacity in seven years.

Greenpeace demanded release of its members, Yevgenia Belikova confirmed."Efforts to cut short the protest act will not thwart the global movement in defense of the Arctic which rallied the support of four million people all over the world. Greenpeace will continue efforts to create an international reserve zone around the North Pole and will do everything possible for the protection of the Arctic region," Greenpeace actvists announced.

Last August Greenpeace activists already attempted to lay a long-term siege to the same Gasprom floating platform and actually blockaded oil prospecting for five days. Alpine climber Sini Saarela was one of the "Greenpeace International" activists to go on board the Gasprom platform last year.

The oil prospecting platform has been drifting on the shelf of the Pechora Sea, pending industrial prospecting. It was built at the "Sevmash" ship building plant in Severodvinsk in the north of Russia and is intended for oil prospecting. It is the first oil prospecting platform in the world to operate under harsh climatic conditions of the Arctic region - in ice-bound waters under air temperatures of 50 degrees Celsius below zero.