Two Russian mini-submarines descended Wednesday more than 4,000 meters to the ocean floor beneath the North Pole, allowing the divers aboard to put the country's flag into a capsule on the seabed.
Expedition leader Artur Chilingarov, who was on board of the MIR 1 three-person submarine, told colleagues on a research ship on the surface that his craft had reached the seabed.
"The landing was smooth, the yellowish ground is around us, no sea dwellers are seen," Chilingarov has said.
The subs and their three-member crews planned to spend several hours in the murky depths conducting a study of the water chemistry and geology near the seabed at the pole, according to Russia's Institute of the Arctic and Antarctic, which organised the expedition.
Expedition members say the biggest challenge for the sub crews will be to find their way back to an opening in the surface of the thick polar pack ice after their dive. They must resurface before exhausting their air supplies.
The deep-diving is performed in the framework of "Arctic 2007" expedition. It aims at establishing the borders of the Russian shelf in the region of the New Siberian Islands.