Marking a new escalation in tensions between countries with the world’s second and third largest economies, Japan formally complained today that China had locked a military radar on one of its ships.

The Washington Post reports this was a “brief but dangerous escalation” in a continued dispute over territory. The Post adds:

“The Chinese ship ultimately unlocked its radar without firing a shot, but the incident underscores how the neighbors — wrangling over uninhabited islands in the East China Sea — are just one mistake away from potential armed conflict.

“Japan on Tuesday lodged a protest with the Chinese government over the incident, which took place near the contested islands that Japan calls Senkaku and China calls Diaoyu.”

According to The Christian Science Monitor, Japanese Defense Minister Itsunori Onodera accused the Chinese of using their radars twice last month.

“It is extremely abnormal to use such fire-control radar, or radar for (weapons) firing,” he said according the Monitor. “The incident could have led to a dangerous situation in case of a misstep.”

“We will sternly call on the Chinese side to refrain from such dangerous acts,” he added.