Things just got a whole lot more serious in the East China Sea.

Last week, Japanese officials announced a Chinese naval vessel had locked its weapons-targeting radar on a Japanese military helicopter and naval vessel in separate January incidents. This new escalatory step in Chinese behavior is one in a series of many, prompting Japan to respond. The tit-for-tat spiraling brings China and Japan closer to one mistake away from potential armed conflict. The two sides need to talk, but questions of sovereignty over a group of disputed islands should be the last thing on their agenda. Instead, Beijing and Tokyo need rules to regulate the interaction of their coast guards, navies, and other vessels and aircraft to prevent a mistake becoming a pretext for conflict.

The dispute between Beijing and Tokyo is not new. Called the Senkaku Islands in Japan and the Diaoyu Islands in China, the dispute involves a group of uninhabited islands controlled by Japan in the East China Sea but claimed by China (and Taiwan). The situation was fairly calm until spring 2012 when then Tokyo governor Shintaro Ishihara made moves to buy three of the islands with a plan to build on them. Because this contradicts central government policy of no landing, no development, then premier Yoshihiko Noda blocked Ishihara by buying them with central government resources instead.

Not surprisingly, Noda’s move angered China. In addition to setting off large-scale, violent and destructive anti-Japanese protests throughout China, it initiated a now near-daily presence of Chinese ships and planes near the islands. Much to the detriment of regional peace and stability, China’s moves have increasingly become bolder, forcing Japan to respond.

At first, Chinese presence near the disputed islands was limited to patrol ships from the maritime and fisheries agencies in nearby waters, mirrored by Japanese coast-guard ships. Then China escalated the situation in December by sending a maritime-surveillance plane into Japanese airspace, forcing Japan to scramble fighter jets. Last month, China upped the stakes by sending a military aircraft into Japanese airspace, forcing Japan to once again scramble jets, which were met—for the first time—by scrambled Chinese jets. Japan responded by announcing it was considering authorizing the firing of warning shots at Chinese planes that enter its airspace. China answered with its most recent provocation of locking onto Japanese military assets with weapons-targeting radar.

This tit-for-tat escalation is worrisome. As China becomes bolder and more provocative, Japan is meeting the assertiveness in-kind. Yet, one mistake could be right around the corner. One need only remember the 2001 EP-3 incident off the coast of Hainan, China, in which a Chinese J-8 fighter jet collided with a US Navy EP-3. The Chinese pilot was killed and the EP-3 was forced to land on Hainan where the crew was detained and interrogated by Chinese officials until the US government made a statement regarding the incident. At root was China’s aggressive monitoring of U.S. presence in airspace over China’s exclusive economic zone, International law says all states enjoy freedom of navigation and overflight in exclusive economic zones, but China disagrees. It took skillful diplomacy to end the confrontation and secure the return of the US servicemen and women.

It is hard to imagine an East China Sea version of the EP-3 incident, one in which Chinese are killed and Japanese are detained, would end as quietly as the 2001 U.S.-China incident. The volatile mix of nationalism and historical grievances in China, combined with a Japanese populace more willing to see their leaders take a hard line with China, means a mistake on any scale has the potential to spiral out of control.

China’s behavior is a naked attempt to erode Japan’s effective control of the area, but the resulting maritime—and increasingly aerial—cat-and-mouse game raises concerns that a mistake could result. This should worry the United States. With Washington stating the islands fall under its security treaty with Japan, Washington is obliged to come to Tokyo’s aid should a conflict occur. Yet, the lines of escalation that would trigger a U.S. response are unclear, as are the levels of such support. Instead, the United States has consistently told both to ratchet down their tensions. It is hard to find evidence that such advice is being taken seriously.

A summit between Prime Minister Shinzo Abe and Chinese Communist Party head Xi Jinping would be a positive development, but it is a short-term fix. Unless China is considering a drawdown of its presence near the islands, a long-term framework is necessary. Barring a solution to the territorial dispute, as long as both countries maintain a maritime and aerial presence around the islands it is in their mutual interest to negotiate an Incidents at Sea (INCSEA) agreement to reduce the chance an incident will occur between their vessels and aircraft and, in the event one does, to prevent it from escalating.

An INCSEA would lay out rules of the road for both countries. It could include things like an agreement to avoid dangerous harassment of their respective aircraft and vessels, steps to avoid collisions between vessels, a set distance for vessels and aircraft to maintain when conducting surveillance, agreed upon signals for ships to use when maneuvering near one another, and an agreement to not simulate an attack against an aircraft or vessel, including locking on weapons-targeting radar. It should also include communication procedures, the establishment of a hotline between their navies and coast guards, and guidelines on how to channel information if an incident occurred, such as utilizing military attachés in their embassies. The point would be to provide structure to their interactions to prevent an incident escalating to conflict.

Such an accord between countries that are rivals or locked in a dispute is not without precedent. During the Cold War, the United States and Soviet Union recognized the potential for unwanted conflict due to an increasing number of incidents of aircraft passing too close to one another, naval vessels bumping into one another, and aircraft or vessels making threatening movements against one another. To provide a framework for their interaction, they signed an INCSEA. Importantly, Russia signed one with Japan as well.

The question of sovereignty over the islands will not be answered anytime soon. In the meantime, the interaction of their vessels and aircraft pose a near daily risk that these two countries could slide unintentionally into conflict. Neither country wants this. Nor does the United States, which could get drawn unwittingly into a conflict over what many see as a group of rocks. Nor does any other country, given that the Chinese and Japanese economies stand as the region’s two largest. Sovereignty questions may need to be put aside for the moment. It is in China’s and Japan’s shared interest to move quickly toward an agreement that will avoid further escalation.

Jeffrey W. Hornung is an Associate Professor at the Asia-Pacific Center for Security Studies in Honolulu, HI and an Adjunct Fellow with the Office of the Japan Chair at the Center for Strategic and International Studies in Washington, D.C. The views expressed in this article are his alone.