Leaders of England, Germany, and Russia regretted the resignation of the Japanese Prime Minister, praising Mr. Abe's leadership efforts in building relations with other countries.

"Mr. Shinzo Abe has really made an invaluable contribution to the development of the Russia-Japan bilateral relationship," President Vladimir Putin's spokesman Dmitry Peskov told Russian news agencies on August 28.

Mr. Peskov said Moscow was sorry that Japanese Prime Minister Shinzo Abe decided to step down due to health problems, adding that his relationship with Putin was "very good".

"Mr. Shinzo Abe has achieved great things as Prime Minister of Japan for his country and for the whole world," British Prime Minister Boris Johnson praised Abe's achievements on Twitter on August 28.

Mr. Johnson added that the UK-Japan relationship has grown from strength to strength, in terms of trade, defense and culture.

"Thank you for the past years of service. I would like to wish you good health", the British Prime Minister wrote.

German Chancellor Angela Merkel on the same day also expressed regret when her Japanese counterpart resigned.

Prime Minister Abe, Japan's longest serving leader, announced his resignation today due to recurrent ulcerative colitis and it takes time to cure.

Mr Abe will remain in office until a successor is decided, likely through a vote of members of the ruling Liberal Democratic Party.