Subi reef, located in the disputed Spratly Islands in the South China Sea, is shown in this handout Center for Strategic and International Studies (CSIS) Asia Maritime Transparency Initiative satellite image taken September 3, 2015 and released to Reuters October 27, 2015.  REUTERS/CSIS Asia Maritime Transparency Initiative/DigitalGlobe/Handout via Reuters

Subi reef, located in the disputed Spratly Islands in the South China Sea, is shown in this handout Center for Strategic and International Studies (CSIS) Asia Maritime Transparency Initiative satellite image taken September 3, 2015 and released to Reuters October 27, 2015.

REUTERS/CSIS ASIA MARITIME TRANSPARENCY INITIATIVE/DIGITALGLOBE/HANDOUT VIA REUTERS

The U.S. Navy deliberately avoided military drills or other actions that could have further inflamed tensions with Beijing during a patrol last week near islands China has built in the South China Sea, U.S. officials said.

“We wanted to assert our rights under international law, but not to the point where we were poking the Chinese in the eye, or where it would unnecessarily escalate the situation,” said a U.S. official, speaking on condition of anonymity.

The official said the destroyer USS Lassen turned off its fire control radars while transiting within 12 nautical miles of Subi Reef and avoided any military operations during that time, including helicopter launches or other drills.

Numerous experts said this cautious approach could in fact reinforce China’s claim to sovereignty over the artificial islands in the Spratly Islands archipelago.

But the U.S. official disputed that assertion.

“It was a freedom-of-navigation operation that was not meant to inflame the situation, which is why they did the transit the way they did,” the U.S. official said.

The Lassen’s commanding officer, Commander Robert C. Francis Jr, told reporters on Thursday that his ship went within six to seven nautical miles of the artificial island.

He said the radar was operating normally at the time for “situational awareness,” and acknowledged the U.S. Navy did not fly helicopters. He described it as both a freedom-of-navigation and a “transit” operation.

China reacted angrily to the patrol, which followed months of U.S. preparation, despite its lack of military drills.

Read more at Reuters: http://www.reuters.com/article/2015/11/06/us-southchinasea-usa-passage-idUSKCN0SV2QK20151106#rcTqhu7FdB0GGIBY.99