From last month's China-US naval standoff in the South China Sea to an intensifying China-Japan rivalry that is prompting Beijing and Tokyo to boost their military presence in the East China Sea, there are worrying signs that the situation in the two contentious bodies of water is becoming more complicated.
With no rules of engagement in place, regional leaders are worried that increasing contact between navies and civilian patrol fleets in the region could easily descend into conflict. But there are signs that some in Beijing are starting to see the benefits of adhering to certain international maritime practices, a move that could soften its view of US military surveillance on its doorstep.
Such recognition is still far from the mainstream view, but academics and some within the government are starting to recognise that a hostile attitude towards close quarters foreign reconnaissance might harm Chinese interests in the long term, according to Jia Qingguo , associate dean at the School of International Studies at Peking University.
Sun Zhe , director of the Centre for US-China relations at Tsinghua University, says there are two views on US surveillance.
"One is that it is a humiliation and we need to resolutely push back. The other view, which is still a minority, is that China will eventually become a great power, and [at that time] it would benefit us to conduct close-in reconnaissance on others," he says.
The latter view, according to Jia from Peking University, was being deliberated as some within the government started to "think about the issue from a long-term perspective".
Incidents at Sea Agreement
The December stand-off between the USS Cowpens, a guided missile warship, and a Chinese amphibious landing vessel that was part of the Chinese aircraft carrier Liaoning strike group, put the spotlight firmly back on Beijing's long-standing objection to US reconnaissance just outside of its territorial waters, usually measured as 12 nautical miles from the coastline.
For more than a decade, the US has tried to establish with Beijing an arrangement similar to the Incidents at Sea Agreement it had with the Soviet Union during the cold war, says Douglas Paal, a vice-president for studies at the Carnegie Endowment for International Peace in Washington.
China rejected the US proposal on the grounds that the Sino-US relationship was "not a cold war relationship in practice," says Paal, director of the American Institute in Taiwan from 2002 to 2006, the unofficial US embassy on the island.
The absence of such operational rules, many analysts have argued, increases the risks of miscalculation as navies and paramilitary fleets from not just China, but also other countries, expand their operations in the region. The intensely contested East and South China Seas have already seen more aerial and maritime patrols since territorial disputes over two sets of uninhabited islands flared up in the past few years.
Analysts are also watching how the air force would implement its air defence identification zone over the East China Sea as airborne surveillance by the US, Japan and South Korea is expected to increase.
Beijing has viewed surveillance activities near its territory as a hostile act and has repeatedly raised the issue with Washington in official level talks. So far, there have been no formal meetings between the two militaries to "try to put positions on the table and negotiate them", says Paal.
As the navy expands its radius of operations - and with an apparent reversal of attitude towards military-to-military exchanges with the US under President Xi Jinping - Paal says the prospects for negotiations on operational guidelines on the sea are improving.
Paal says that since 1989, military relations between the US and China have stalled: "When they were eager, we were not. When we were eager, they were not."
Xi has more or less reversed his predecessor's "no co-operation" approach, which was triggered by US President Barack Obama's decision to sell arms to Taiwan, according to Paal.
As a result, military exchanges have since been increasing.
Beijing's response to the December 5 standoff has been restrained and the defence ministry confirmed late last month that preparations were still on track for the People's Liberation Army (PLA) to make its maiden appearance in the biannual Pacific Rim military exercises in Hawaii this year, where 22 countries will participate.
During a security forum in Singapore last June, a PLA senior colonel revealed that Beijing had reciprocated US military surveillance by occasionally sending ships and planes to US exclusive economic zones (EEZ), presumably in Guam and Hawaii, according to security expert Rory Medcalf, who was present at the discussion panel when the remarks were made.
"That could be seen as the beginning of recognition that as China becomes a world power, it conducts surveillance in other countries' [exclusive economic zones]," says Medcalf, director of the International Security Programme at the Lowy Institute in Australia.
Such recognition could pave the way for Beijing's reinterpretation of the United Nations Convention on the Laws of the Sea (UNCLOS), which defines the rights and responsibilities of nations in their use of the oceans.
If China begins to conduct similar surveillance on other countries, there could be a shared understanding on the legality of such operations, and "that could, ironically, reduce risks," Medcalf says.
The PLA Navy has increased military drills in the western Pacific, to the south and east of Japan, and the South China Sea. Paramilitary patrols in disputed areas have also become a new norm in disputed areas as Beijing aims to establish its presence.
Medcalf sees the presence of Chinese naval vessels in the US exclusive economic zone as a potential game changer, as Beijing's interpretation of the UNCLOS is that freedom of navigation does not include the right to conduct surveillance in another country's exclusive economic zone, which extends up to 200 nautical miles from the coast. But the US and other countries view military surveillance as legitimate and peaceful activity allowed under UN laws.
A history of skirmishes
These differing interpretations have triggered other incidents in the South China Sea. In 2001, a Chinese fighter jet collided with a US aircraft in the area, resulting in the death of a Chinese pilot and a chill in bilateral ties. In 2009, a stand-off between the American surveillance ship USNS Impeccable and several Chinese surveillance vessels in China's EEZ in the South China Sea prompted arguments over freedom of navigation in waters close to China's territory.
It is not clear whether the December 5 stand-off between the US cruiser and the Chinese vessel occurred within China's EEZ, but Washington said its navy was "lawfully operating" when the Chinese vessel came within 500 yards of the Cowpens and "manoeuvering" was required to avoid a collision.
Chinese government reports said the US vessel was conducting surveillance and "harassing" the Liaoning aircraft carrier.
Whether Beijing's own need for surveillance will translate into a shift in its view on foreign surveillance of its own shores will be subject to domestic and regional uncertainties. But as the PLA Navy sails further out into international waters, bringing it closer to the coastlines of other countries, "they would like something like the Incident at Sea Agreement to protect them", says Carnegie's Paal.
"China is just at the beginning of evolving into a maritime power. It's a learning process that needs to be undertaken," he says.