The Philippine government has accused China of using a laser to interfere with their coast guard operations. According to the Philippine military, a Chinese vessel shone a laser at a Philippine coast guard ship in the South China Sea on Sunday night.

The incident is the latest in a series of disputes between the two countries over the South China Sea, a strategic waterway through which more than $3 trillion in global trade passes each year.

The Philippine military said the Chinese vessel was stationed near a reef claimed by both countries, and that the laser “endangered the safety” of the Philippine coast guard ship. They said the Chinese vessel left the area shortly after the incident.

The Chinese government has not yet commented on the incident, but the Philippine military has called for an investigation into the matter.

The incident is likely to further increase tensions between the two countries, who have been locked in a dispute over the South China Sea for years. The two nations have clashed over fishing rights, oil exploration, and the construction of artificial islands in the area.