WASHINGTON » Members of Congress urged the Obama administration today to order more naval operations close to disputed islands in the South China Sea. The State Department said Beijing risks conflict and isolation through its assertive behavior in those waters.

Twice since the fall, the U.S. Navy has sailed by artificial islands built by China, and Deputy Secretary of State Antony Blinken told the Senate Foreign Relations Committee that such operations will take place regularly.

Republicans said such “freedom of navigation” operations cruising within 12 nautical miles of the manmade islands — what China might consider as their territorial waters — should become routine.

“I don’t why we are not doing it weekly, or monthly,” said the committee chairman, GOP Sen. Bob Corker of Tennessee.

He contended that China has positioned itself as a geopolitical rival of the United States.

“Merely managing differences with China is not a successful formula particularly when such management cedes U.S. influence and places American interest at risk in the Indo-Pacific and beyond,” Corker said.

Blinken said China was alienating its neighbors and risked “conflict, instability and isolation’ unless it changed its approach and clarified its claims in the South China Sea in accordance with international law.

“As long as the United States remains fully present in the region, any tactical advantage that China derives from some of these outposts will be vastly outweighed by the net effect of surrounding itself with increasingly angry, increasingly suspicious neighbors who are increasingly close to the United States,” he said.

China claims virtually the entire South China Sea, an area that contains some of the world’s busiest sea lanes. Although the U.S. is not a claimant, it says it has a national interest in freedom of navigation and maintaining stability there.

Tensions have escalated in the past two years as China has reclaimed more than 3,000 acres of land, and constructed airstrips, ports and radar stations.

China says those developments are mainly for civilian purposes and that U.S. military activities — especially the sailing of ships close to the newly built islands — threaten China’s security.