TOKYO—Japan and the Philippines plan to hold their first ministerial security talks online later this month, apparently aimed at bolstering cooperation in countering China's increasing maritime assertiveness in the South and East China seas, diplomatic sources said Wednesday.

The Philippines will be the 9th country with which Japan has held the so-called 2-plus-2 talks, which involve the countries' foreign and defense ministers, and only the second Southeast Asian country following Indonesia to do so.

• Why tensions are rising over Taiwan

The launch of such talks is in line with an agreement made in November last year between Japanese Prime Minister Fumio Kishida and Philippine President Rodrigo Duterte, whose country has overlapping territorial claims with Beijing in the South China Sea.

• Biden vows to stand with Southeast Asia in defending freedom of seas, democracy

Japan has also formed a two-plus-two framework with the United States, Australia, Britain, France, Germany, India, and Russia.

With Japan and the United States stepping up its watch over the Chinese military's movements beyond what China views as the "first island chain," a Japanese government source has described the Philippines as a "strategic point for security" given its geographical location.

The first island chain is a sea defense line stretching from the Japanese archipelago through Taiwan and the Philippines.

Japan will be represented by Foreign Minister Yoshimasa Hayashi and Defense Minister Nobuo Kishi and the Philippines by Foreign Secretary Teodoro Locsin and Defense Secretary Delfin Lorenzana.

According to the sources, the ministers are expected to agree on achieving a "free and open Indo-Pacific," referring to an initiative by Japan and the United States that is widely seen as a counter to China's growing assertiveness in the area and increasing economic clout in the region.

The ministers are also set to affirm the importance of peacefully resolving disputes in line with international law, according to the sources.

• Chinese ambassador: Support of Taiwan independence could spark US military conflict with China

FROM THE ARCHIVES

Watch more in iWantv or TFC.tv