Five Chinese vessels “shadowed and aggressively maneuvered in dangerously close proximity” to the USNS Impeccable, a US surveillance ship operating in international waters in the South China Sea Sunday, the Pentagon has disclosed.

Two of the Chinese vessels closed to within 50 feet (15m) of the Impeccable, waving Chinese flags and telling the ship to leave the area. The Impeccable sprayed water from its fire hoses at one of the boats to protect itself.

This is the third incident in a week. On Friday, a Chinese frigate crossed Impeccable’s bow at a range of about 100 yards, according to the Pentagon, and on March 4, a Chinese Bureau of Fisheries Patrol vessel shinned a high-intensity spotlight at the USNS Victorious several times.

The USNS Impeccable is a 5,368 ton, 281 foot (86m) Victorious-class ocean surveillance ship. The main role of the ship is to track “undersea threats,” or in other words, submarines.

Coming with 50 feet of a ship this size is aggressive to say the least. If there had been a collision, the incident would be larger again, and could possibly have been used as a pretext for a breakdown in Chinese-American relations by either side. The Chinese are undoubtedly annoyed about American ships lurking off their coast, but the presence of the ships is fair under international law: these ships were in international waters and had a right to be there. Lets hope that there’s not any more close calls or worse still, an actual incident. It might not end up with a war, but if China cut off its borrowing to the United States, the net result wouldn’t be that far removed.