Blinken made the comments Sunday, in a statement marking the fifth anniversary of a ruling by an independent arbitration tribunal rejecting China's expansive territorial claims over the waterway, siding with the Philippines.
Tensions in the South China Sea, which is also contested by Brunei, Malaysia, Taiwan and Vietnam have ratcheted up this year, with Manila accusing Beijing of trying to intimidate its coast guard vessels, as well as sending its so called "maritime militia" to crowd out Philippine fishing boats.
The US' top diplomat said the US could invoke the US-Philippine mutual defense pact in the event of any Chinese military action against Philippine assets in the region. "We also reaffirm that an armed attack on Philippine armed forces, public vessels, or aircraft in the South China Sea would invoke US mutual defense commitments under Article IV of the 1951 US-Philippines Mutual Defense Treaty," Blinken said.
