Relations between the Chinese and US navies are their "best in history" and exchanges between the two will become more systematic in the future, China’s military on Friday cited the country’s naval chief as telling visiting U.S. officers. The comments by navy chief Wu Shengli come as Washington considers conducting freedom-of-navigation operations within 12 nautical miles of artificial islands China has built in the disputed South China Sea, without saying when it would do so. Such a move is likely to infuriate Beijing. READ MORE: Beijing on alert for U.S. Navy 'incursion' near artificial islands in South China Sea China and the United States had worked hard to increase military interaction, holding joint drills and agreeing rules on encounters at sea and in the air, Wu said, according to the official People’s Liberation Army Daily . “At present, relations between the Chinese and US navies are at their best time in history,” Wu was cited as saying. “Exchanges and communications are more trusting and effective.” This has not come easily, though, and is the result of hard work by both sides, he added. “In the future, exchanges between frontline forces from both countries will gradually become more systematic,” Wu said. There was no mention of the South China Sea. The US naval delegation Wu met earlier this week and visited China’s sole aircraft carrier. The military’s newspaper said they also visited a submarine school and a command college. READ MORE: China navy warns US spy plane in disputed South China Sea China-US relations have become increasingly strained over Beijing’s territorial claims in the South China Sea, through which US$5 trillion in ship-borne trade passes every year. Vietnam, the Philippines, Malaysia, Taiwan and Brunei also have claims in the area.