WASHINGTON (Reuters) - The United States is considering sailing warships close to China’s artificial islands in the South China Sea to signal it does not recognize Chinese territorial claims over the area, a U.S. defense official said on Thursday.

The Financial Times newspaper cited a senior U.S. official as saying U.S. ships would sail within 12-nautical-mile zones that China claims as territory around islands it has built in the Spratly chain, within the next two weeks.

The Navy Times quoted U.S. officials as saying the action could take place “within days,” but awaited final approval from the Obama administration.

A U.S. defense official declined to confirm that any decision had been made, but referred to remarks in congressional testimony last month by U.S. Assistant Secretary of Defense David Shear, that “all options are on the table.”

“We are looking at this,” the official said, on condition of anonymity.

White House spokesman Josh Earnest said he was aware of the media reports but did not have any comment on future policy decisions.

Earnest told a regular news briefing that any such move “should not provoke significant reaction from the Chinese.”

“This is something the United States has done on several other occasions because the president is committed to the principle of freedom of navigation in the South China Sea.”

Shear, the U.S. assistant secretary of defense, told the Senate Armed Services Committee last month there had been no U.S. patrols within 12 miles of the Chinese-claimed islands since 2012.

Chinese dredging vessels are purportedly seen in the waters around Mischief Reef in the disputed Spratly Islands in this still image from video taken by a P-8A Poseidon surveillance aircraft provided by the United States Navy May 21, 2015. REUTERS/U.S. Navy/Handout via Reuters ATTENTION EDITORS - THIS PICTURE WAS PROVIDED BY A THIRD PARTY. REUTERS IS UNABLE TO INDEPENDENTLY VERIFY THE AUTHENTICITY, CONTENT, LOCATION OR DATE OF THIS IMAGE. THIS PICTURE IS DISTRIBUTED EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS. EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS

In May, the Chinese navy issued eight warnings to the crew of a U.S. P8-A Poseidon surveillance aircraft when they conducted flights near China’s artificial islands, according to CNN, which was aboard the U.S. aircraft.

China claims most of the South China Sea, where the Spratly islands are located and $5 trillion in ship-borne trade passes every year. The Philippines, Vietnam, Malaysia, Brunei and Taiwan also have overlapping claims.

CHINA WATCHING CLOSELY

Chinese Foreign Ministry spokeswoman Hua Chunying told a regular news briefing on Thursday that China was paying attention to the reports of impending U.S. naval action, and that it and the United States have maintained “extremely thorough communication” on the South China Sea issue.

“We hope the U.S. side can objectively and fairly view the current situation in the South China Sea, and with China, genuinely play a constructive role in safeguarding peace and stability in the South China Sea,” she said.

U.S. Defense Secretary Ash Carter said last month, in reference to China’s South China Sea claims, that the United States would “fly, sail, and operate wherever international law allows, as U.S. forces do all over the world.”

U.S. President Barack Obama said he told Chinese President Xi Jinping he had “significant concerns” about the islands when Xi made his first state visit to Washington late in September.

Xi said at the time China had no intention to militarize the islands, but Washington analysts and U.S. officials say China has already begun creating military facilities, and the only question is how much military hardware it will install.

Admiral Harry Harris, commander of U.S. forces in the Pacific, has said China’s development of the islands, including the building of runways suitable for military use, was of “great concern” and a threat to the region.

In congressional testimony on Sept. 17, Harris said the United States should challenge China’s claim to territory in the South China Sea by patrolling close to the artificial islands and that the U.S. was considering going within 12 miles of them.