Foreign ministers of the U.S., Japan, India and Australia - countries with some of the strongest militaries in the Indo-Pacific - had sideline talks Tuesday at their meeting in Tokyo to discuss curbing China's "expansionism."

The four are members of the Quadrilateral Security Dialogue, or QSD and also known as Quad. Quad was a 2017 initiative of former Japan prime minister Shinzo Abe.

This is the second Quad meeting at a ministerial level. The first was in September a year ago in New York.

Quad will establish an "Asian arc of democracy." This will include countries in Central Asia, Mongolia, South Korea, Southeast Asian countries and "virtually all the countries on China's periphery - except for China itself," the group says.

Quad wants to temper China's growing imperialism. At the talks are U.S. Secretary of State Mike Pompeo, Australia Foreign Minister Marise Payne, India's Minister of External Affairs Subrahmanyam Jaishankar and Japan Foreign Minister Toshimitsu Motegi.

New Japan Prime Minister Yoshihide Suga will make his first international diplomatic appearance at the meeting. Much of the discussion will be about a "free and open Indo-Pacific," analysts said. It has its own acronym, too - FOIP. The four countries will seek to ally "like-minded" countries alarmed by China's unrestrained military and economic expansionism, they said.

The aspirational aim of FOIP is to ensure "sovereign and independent nations, with diverse cultures and many different dreams can all prosper side-by-side, and thrive in freedom and in peace," according to documents.

Quad has been likened to Asia's version of NATO. It has long been anticipated Quad would eventually transform into a military alliance that will include Southeast Asian countries and South Korea, analysts said.

Suga will attend some of the Quad meetings and will hold separate talks with Pompeo on the Japan-U.S. alliance and a FOIP.

"The world is possibly becoming even more unpredictable and uncontrollable due to heightening selfish nationalism and growing tension between the U.S. and China," Suga said in an interview.

He will pursue diplomacy with the Japan-U.S. alliance as its cornerstone. He will "strategically promote the FOIP" and will boost FOIP in a visit to Southeast Asian countries later in October.

Suga wants to regularize Quad foreign ministers' talks and broaden cooperation with other Indo-Pacific countries.

However, a "shared threat perception of China doesn't mean shared views on what to do and if it's possible to build the Quad into something along the lines of NATO," according to Jeff Kingston, director of Asia studies at Temple University's Japan campus.