The top uniformed officer of Japan's Self-Defense Forces said Thursday Japan is in communication with the United States regarding U.S. President Donald Trump's plan for a military coalition to safeguard commercial shipping in the Middle East.

"It's true that Japan and the United States are communicating over a range of matters regarding the situation (in the Strait of Hormuz)," Koji Yamazaki, the chief of the SDF's Joint Staff, told a press conference.

Calling the strait off Iran and Oman "a vitally important region in terms of our country's energy security," Yamazaki said the Japanese government is "keeping a close watch on developments" of exchanges between the countries concerned.

(File photo shows Koji Yamazaki)

But Yamazaki refrained from elaborating on talks with his American counterpart Marine Gen. Joseph Dunford, the chairman of the Joint Chiefs of Staff. He also declined to say whether they are discussing an SDF dispatch to the Middle East.

Due to restrictions by its pacifist Constitution, the bar remains high for Japan to send troops to the region.

On Tuesday, Dunford put forward the idea of forming a coalition of the willing to ensure freedom of navigation in key corridors, through which major oil exports flow to the world such as the Strait of Hormuz, amid increasing bilateral tensions between the United States and Iran over Tehran's nuclear program and sanctions against it.

The plan was floated following attacks on two oil tankers including one operated by a Japanese firm last month.

Trump has expressed frustration over what he perceives to be an "unfair" bilateral security treaty with Japan, saying it should be changed, though he denied he would scrap it.

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