According to the Taiwan Coast Guard, ships are sent in reaction to a China operation.

The “law enforcement operation” was in response to negotiations between Japan and the Philippines to establish a border in the impacted waters, according to Chinese official media on Saturday.

China, which maintains that Taiwan is a part of its territory, referred to the negotiations as “illegal” and asserted that it has sole authority over the waters.

According to a statement from the Taiwanese coast guard, the Chinese ships have been observed “throughout the entire process,” and Taiwan “has deployed the necessary vessels to respond appropriately.”

Taiwan reported that it had seen four Chinese government ships leaving the port of Xiamen that had ventured outside Taiwanese-controlled waters southwest of the island.

More than five ships were sent by Taiwan’s coast guard “to assist with surveillance.”

According to state news agency Xinhua, Beijing’s transport ministry organized maritime police from the coastal provinces of Guangdong and Fujian on Saturday to “conduct a special maritime traffic law enforcement operation in waters east of Taiwan Island.”

The report did not specify whether ships were sent to the region by maritime police or how long the operation lasted or if it was still in progress.

According to Xinhua, the operation was “a necessary action taken against Japan and the Philippines’ unilateral announcement they would start ‘negotiations on delimiting a maritime boundary'” near Taiwan.

Taiwan stated on Wednesday that it ought to be consulted regarding the negotiations between Japan and the Philippines.