A China Coast Guard vessel was seen closely monitoring a Philippine civilian mission bound for Pag-asa Island in the West Philippine Sea early Friday morning, according to the civil society group Atin Ito.

According to authorities, the China Coast Guard ship, identified with bow number 3103, was detected at around 7:20 a.m. while positioned approximately 3.2 nautical miles from the civilian mission vessel MV Kapitan Felix Oca.

At the time, the Philippine-flagged vessel was about 90 nautical miles from Manila and roughly 60 nautical miles west of Mindoro, the group said.

The civilian convoy is part of an initiative organized by Atin Ito to assert the country’s presence in contested waters.

As of publication, the Chinese Embassy in Manila has not released any comment on the matter.