After decades of American surveillance operations off China's coast, the Chinese military may be starting to respond in kind, according to reports coming out of the giant Asian security confab known as the Shangri-La Dialogue, which took place in Singapore over the weekend.

While Chinese surveillance ships and aircraft won't be skirting the fringes of the California coast anytime soon, they may have already begun sniffing around Guam and Hawaii, writes former Australian diplomat Rory Medcalf, now with the Lowy Institute for International Policy - an Australian think tank - who attended the conference.

"It was striking to hear a Chinese military officer reveal in an open discussion at the conference this week that China had "thought of reciprocating" by "sending ships and planes to the US EEZ exclusive economic zone," and had in fact done so "a few times," although not on a daily basis (unlike the U.S. presence off China)."

This was news to me. It turns out, from discussions with several maritime security experts in the margins of the conference, that rumours have been circulating for some time of China sending ships on missions to waters off U.S. territory - not the continental U.S., but probably Hawaii and possibly Guam too.

This would fit with China's rapid buildup of military technology, which seems aimed at allowing Beijing to project military power throughout the Western Pacific.

In recent years the Chinese military has fielded ballistic missiles meant to keep American aircraft carriers far from its shores; stealth jets like the J-20, which appear to be designed to either strike American ships and bases or intercept U.S. bombers; a stealthy UAV similar to the U.S. Navy's concept for a long-range stealth drone that can penetrate advanced air defenses; an aircraft carrier (with more on the way); new destroyers equipped with Aegis-style radars; submarines and replenishment ships; and a new fleet of maritime surveillance and radar planes.

Medcalf points out that China used to dangerously confront U.S. surveillance ships and aircraft, claiming they were violating the "sovereignty" of its exclusive economic zone, which extends 200 nautical miles from shore (and is not actually considered sovereign territory under international law). China may now have realized this strategy wasn't working and decided instead use the same tactic to gather intel on U.S. activities.

We might even see more Chinese surveillance ships and perhaps carrier-based surveillance planes in the waters off U.S.-owned Islands, or perhaps the Eastern Pacific, as the PLA Navy gets more comfortable conducting lengthy cruises in waters far from home in the coming decades.