In a rare gesture, Prime Minister Narendra Modi, US President Joe Biden and Australian PM Anthony Albanese came out with a joint statement on Saturday mourning the death of Japanese leader Shinzo Abe and recalling his contribution to the formation of the Quad and efforts towards a free and open Indo-Pacific.

The leaders of the Quadrilateral coalition or Quad vowed to "redouble" their work to ensure a peaceful and prosperous Indo-Pacific to "honour" Abe's memory and described him as a "transformative leader" for Japan and its relations with each of the three countries.

The joint statement came a day after Modi, Biden and Albanese issued separate condolence messages expressing shock and grief over the assassination of the longest-serving prime minister of Japan. On Friday, Modi wrote a blog in memory of Abe.

The 67-year-old Japanese leader died after being shot while giving a campaign speech in the city of Nara on Friday morning, triggering shock and grief by leaders across the world.

Abe, the grandson of former prime minister Nobusuke Kishi, played a pivotal role in shaping the broad contours of the Quad or Quadrilateral coalition in face of increasing Chinese assertiveness in the Indo-Pacific.

In their statement, Modi, Biden and Albanese said Abe was a "transformative leader" for Japan and worked tirelessly to advance a shared vision for a free and open Indo-Pacific.

The Quad comprises India, the US, Japan and Australia.

"We, the leaders of Australia, India, and the United States, are shocked at the tragic assassination of former Japanese Prime Minister Shinzo Abe," the leaders said in the statement.

"Prime Minister Abe was a transformative leader for Japan and for Japanese relations with each one of our countries. He also 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.

Modi, Biden and Albanese said they will honour Abe's memory by "redoubling our work" towards a peaceful and prosperous Indo-Pacific region.

"Our hearts are with the people of Japan -- and Prime Minister Kishida -- in this moment of grief. We will honour Prime Minister Abe's memory by redoubling our work towards a peaceful and prosperous region," they said.

Prime Minister Modi had met Abe in May when he travelled to Japan to attend a summit of the Quad leaders.

Abe was prime minister of Japan from 2006 to 2007 and then again for a second stint from 2012 to 2020.

Meanwhile, UN Secretary-General Antonio Guterres said he is deeply saddened by Abe's "horrific killing", calling it an "act that has profoundly shocked Japanese society in a country with one of the lowest rates of gun crime."

A statement issued by the UN chief's spokesperson said Abe will be remembered as a staunch defender of multilateralism, respected leader, and supporter of the United Nations.

"The Secretary-General recalls Shinzo Abe's commitment to promoting peace and security, championing the Sustainable Development Goals and advocating for universal health coverage. As the longest-serving Prime Minister, he was dedicated to reviving his country's economy and serving the people of Japan," it added.

The UN Secretary-General expressed his deep condolences to Abe's family and the people and Government of Japan.

Permanent Representatives and diplomats of the 15 nations of the UN Security Council, before their meeting on the situation in the Middle East, stood up to observe a minute of silence in the memory of and to pay their respects to Abe and the former President of Angola Jose Eduardo dos Santos, who passed away in Spain.

Brazil's Ambassador to the UN Ronaldo Costa Filho, the current President of the Council, said that on behalf of the Security Council, he expresses "our sadness and shock" at the "senseless assassination" of Abe. He also extended the Council's sadness over Santos's passing.

"The members of the Security Council express their condolences and deepest sympathy" to the families of Abe and Santos and to the governments and people of Japan and Angola "on their tragic losses," Filho said. Japan will begin its two-year term as a non-permanent member of the UN Security Council from January 1, 2023, the 12th time that Tokyo will be in the Council as an elected member since joining the UN in 1956, more than any other UN member state. Japan will begin its tenure on the UNSC as President of the 15-member Council for the month of January.

Ruling party surge

Japan’s ruling Liberal Democratic Party could receive a surge of support in an upper house election on Sunday following the assassination of former Prime Minister Shinzo Abe, the party’s leading statesman and power broker.