The leaders of the Quad have mourned the assassination of former Japan Prime Minister Shinzo Abe, whose vision led to the founding of the Indo-Pacific group.
In a joint message on Friday, Prime Ministers Narendra Modi of India and Anthony Albanese of Australia, and US President Joe Biden said the former Japanese prime minister "played a formative role in the founding of the Quad partnership, and worked tirelessly to advance a shared vision for a free and open Indo-Pacific".
They said that they were "shocked at the tragic assassination" of Abe, "a transformative leader for Japan and for Japanese relations with each one of our countries".
Saying their "hearts were with the people of Japan - and Prime Minister (Fumo) Kishida - in this moment of grief," they declared, "We will honour Prime Minister Abe's memory by redoubling our work towards a peaceful and prosperous region".
Abe was among the first to envision with then Indian Prime Minister Manmohan Singh, the group of democracies as a potential counterweight to China in the Indo-Pacific taking forward the cooperation of the four countries in providing relief during 2004 tsunami.
He sketched its outlines in a speech to Indian Parliament in 2007.
His idea was to expand the trilateral cooperation between the US, Japan and Australia to include India, an emerging dynamic force in the region.
Although it did not make much headway at that time, Abe revived it ten years later during his second term as prime minister.
At his initiative, Prime Minister Narendra Modi, Malcolm Turnbull, the then-prime minister of Australia, and former US President Donald Trump held their first Quad summit in 2017 in Manila.
From there on, the Quad has taken off with support growing despite the changes in governments in the US, Japan and Australia boosted by the growing aggressive posture of China in the Indo-Pacific.