India on Friday declared a one-day national mourning on Saturday in memory of former Japanese Premier Shinzo Abe, as Prime Minister Narendra Modi expressed "shock" at the assassination of "one of my dearest friends".

"I am shocked and saddened beyond words at the tragic demise of one of my dearest friends, Shinzo Abe. He was a towering global statesman, an outstanding leader, and a remarkable administrator. He dedicated his life to make Japan and the world a better place," Modi tweeted.

Read: Japan ex-leader Shinzo Abe assassinated while giving speech

PM Modi also lauded 67-year-old Abe for his "immense contribution to elevating India-Japan relations to the level of a Special Strategic and Global Partnership".

"Today, whole India mourns with Japan and we stand in solidarity with our Japanese brothers and sisters in this difficult moment. As a mark of our deepest respect for former Prime Minister Abe Shinzo, a one day national mourning shall be observed on 9 July 2022," he wrote.

Recalling his association with Abe, Modi said that he had got to know him "during my tenure as Gujarat CM and our friendship continued after I became PM". "His sharp insights on economy and global affairs always made a deep impression on me."

Read: Japan ex-leader Shinzo Abe apparently shot, in heart failure

"During my recent visit to Japan, I had the opportunity to meet Mr. Abe again and discuss many issues. He was witty and insightful as always. Little did I know that this would be our last meeting. My heartfelt condolences to his family and the Japanese people," the Indian PM wrote.

The former Japanese PM was assassinated by a former Navy personnel while giving a campaign speech in the southern city of Nara. He was pronounced dead five hours later at a hospital where he was airlifted to.