Lawmakers want the United States to be more aggressive toward China's creation of artificial islands to bolster its claim to much of the South China Sea before it sparks a war in the region.

Countries in the region are alarmed by China's reclamation of some 2,000 acres as part of what one U.S. admiral calls a "Great Wall of Sand" and its construction of an airstrip on a reef in the disputed Spratly Islands. And they are looking to Washington to help stop it.

Administration officials told the Senate Foreign Relations Committee on Wednesday that their diplomatic efforts to contain China's ambitions in the South China Sea and the East China Sea to the north were paying off, but lawmakers were skeptical.

"Diplomacy only works when people see there's a real price to pay. I don't see any price being paid at all," said Chairman Bob Corker, R-Tenn.

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