MANILA, Philippines — A suspected Chinese Maritime Militia vessel ran aground at Pagasa Reef 1 last Saturday, the Philippine Coast Guard (PCG) reported.

The vessel, identified by bow number 16838, was about one nautical mile from Pagasa Island when it grounded. Authorities said the incident was likely caused by rough sea conditions with waves between 2 to 3 meters and strong winds.

PCG personnel on Pagasa Island attempted to contact the grounded vessel to assess its condition and offer assistance to prevent damage to the reef but received no response. After about three hours, the vessel freed itself without outside help.

The China Coast Guard ship with bow number 5102 communicated with the grounded vessel but did not approach due to risks of grounding in shallow waters, the PCG said.

The PCG and other agencies are set to conduct an environmental damage assessment to evaluate possible harm to the reef caused by the vessel’s grounding.