Artur Chilingarov, an adventurer and deputy speaker of Russia's parliament, led two Russian mini-submarines to the bottom of the Arctic Ocean beneath the North Pole, where he collected gravel and planted the Russian flag.

ECONOMIST: Ventures into the near-abroad

The mission to check on the American detainees was proposed earlier this month by Vladimir Ryzhkov, deputy speaker of the Duma, Russia's lower house of parliament.

CNN: GOP lawmaker criticizes White House rebuff of POW mission