In a statement released on Friday, the ministry reported that Chinese fishing boats illegally operated around a reef in the Spratly Islands, which is in the Philippines’ exclusive economic zone.

The ministry said the boats also blocked navigation by other ships by spreading fishing nets and floating buoys.

The ministry added that private transport boats hired by the Philippine government were also shadowed by Chinese coast guard vessels while navigating toward the reef.

The ministry says, “China has no right to fish, monitor or interfere with the Philippines’ legitimate activities therein.” It urged the Chinese side to comply with international law.

The reef is nearly 200 kilometers west of the Philippines’ western island of Palawan.

An arbitration tribunal in The Hague in 2016 rejected China’s claim on almost all of the South China Sea and acknowledged the reef as being within the Philippines’ exclusive economic zone.

Last Thursday, the ministry issued a separate protest relating to more than 50 Chinese fishing boats that had stayed for nearly two months in a different part of the South China Sea, urging them to leave the zone immediately.