ABOARD THE METROPOLIA PLATFORM, Russia Russian explorers plunged to the bed of the world's deepest lake on Tuesday in a show of Moscow's resurgent scientific ambitions, but had to withdraw a claim to have set a new record.
The mission to the depths of Siberia's Lake Baikal was led by Artur Chilingarov, a scientist and Kremlin-backed member of parliament who was part of an earlier mission to the North Pole that sparked criticism in the West.
The mission's twin submersibles, used last year to plant a Russian flag on the seabed under the North Pole, descended 1,580 metres (5,180 feet) to the lake bed. This was well short of their 1,680 metre target, which would have set a world record for freshwater submersion.
As the mission unfolded live on state television, officials were quick to declare it the world's deepest dive. "This is a world record," Interfax news agency quoted one of the expedition's organisers as saying.
The scientists believed they had discovered a point in the lake deeper than the one hitherto considered its bottom, at 1,637 metres down, which had already been visited by another Russian submersible several years earlier.
But when the six crew returned hours later, organisers said they had reached the lake floor at a depth of only 1,580 metres.
"There was no record. But we'll continue exploration," said Chilingarov, who oversaw the operation from a mission-control point on the Metropolia Platform floating on the lake.
Tucked away in the remote hills of south-east Siberia where Russia borders China and Mongolia, Baikal, the world's deepest and oldest lake, is revered in Russia as a national treasure.
Formed 25 million years ago and home to 20 percent of the world's unfrozen freshwater, it also hosts some of the world's rarest species of fish and other aquatic life, and lies on significant mineral resources.
The expedition collected samples from the seabed and, echoing the mission to the North Pole, placed a pyramid adorned with the Russian tricolour on the lake bed.
"The bottom of the lake was very flat," crew member Vyacheslav Nagovitsyn, also head of the nearby Russian region of Buryatia, said in televised remarks. "Visibility was excellent when we illuminated it."
Russia used the mission to the North Pole to stake a symbolic claim to the energy riches of the region, believed to hold vast resources of oil and natural gas. Canada at the time accused Russia of behaving like a 15th-century explorer.