PM Modi, US President Biden, Australia PM Morrison and Japan PM Suga - leaders of the four Quad nations. NEW DELHI: Top Indian and American military commanders on Wednesday said navies of the “Quad” countries could seamlessly swing into action for a joint military operation if the need arises to tackle a threat and ensure a free, open and inclusive Indo-Pacific. The messaging about the Quad grouping of India, the US, Japan and Australia against a belligerent and expansionist China in the Indo-Pacific was clear. It also came a day after the Chinese official media gleefully latched onto the recent passage by a US warship through India’s EEZ without prior consent to ask New Delhi to re-evaluate its ties with Washington and shed its “illusions”.