Japan’s Prime Minister Shinzo Abe lashed out at China Wednesday for a decision by a Chinese frigate to put a radar lock on a Japanese navy ship in the East China Sea last week.

Abe told the parliament that the move could have led to an "unpredictable situation" and called on China to avoid an "unnecessary escalation."

"At a time when it seemed there are signs of improvement towards increasing talks between Japan and China, having this sort of one-sided provocative action taken by the Chinese is extremely regrettable," Abe was quoted as saying by the BBC.

Abe’s remarks came a day after Japan’s Defense Minister Itsunori Onodera announced that “something like fire-control radar was directed at a Japan Self-Defense Force Maritime escort ship in the East China Sea” Jan. 30, as quoted by the AFP.

He said similar radar was beamed at a Japanese military helicopter Jan. 19.

“Directing such radar is very abnormal,” Onodera said. “We recognize it could create a very dangerous situation if a single misstep occurred. We will seek the Chinese side’s self-restraint from taking such dangerous action.”

Japan's Foreign Ministry lodged a protest with the Chinese embassy in Japan Tuesday.

The dispute between Japan and China over a tiny group of uninhabited islands, known as Senkaku in Japan and Diaoyu in China, escalated in recent months to the point that Beijing and Tokyo scrambled fighter planes Jan. 11 over airspace incursions near the contested region.

The incident was triggered when the Chinese government sent a civilian surveillance plane to fly near the disputed islands.

Tokyo, in response, ordered F-15 fighter jets to tail the Chinese surveillance plane, which prompted Beijing to send their own J-10 fighters.

In a similar incident Jan. 15, Japan’s Air Self-Defense Force (ASDF) scrambled fighters to the Islands after a propeller-driven airplane belonging to China's State Oceanic Administration flew about 120 kilometers north of Kubajima, one of the islets, the Yomiuri Shimbun reported.

There has been no official reaction from Beijing over the radar act, but the U.S., Japan’s treaty ally, said such actions “escalate tensions and increase the risk of an incident or a miscalculation, and they could undermine peace, stability and economic growth in this vital region.”

U.S. State Department spokeswoman Victoria Nuland added that Secretary of State John Kerry spoke to China's Foreign Minister Yang Jiechi Tuesday but declined to reveal whether the island row between Japan and China had been raised during the talks.

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