U.S. keeps watchful eye as China builds 'Great Wall of Sand'

The crew of Pelican One keeps a watchful eye as the U.S. Navy patrol plane swoops low to identify a ship operating near waters off southwestern Japan that China now claims as its territory.

After a radio check and a close look confirms the ship is a harmless Panama-flagged commercial tanker, Pelican One veers off and resumes a patrol that can last up to 12 hours and takes the plane thousands of miles from its base in Okinawa, Japan.

These missions have taken on new urgency as the U.S. military keeps a closer eye on China's increasingly assertive territorial claims, including an unprecedented island-building campaign in the nearby South China Sea.

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