Representatives from a record 67 countries will attend this year's peace memorial service marking the 1945 US atomic bombing of Hiroshima, the municipal government has said.
The figure tops the previous record of 59 countries in 2009.
The world's first atomic-bombed city asked a total of 149 countries to send delegates, city officials said on Tuesday.
UN Secretary General Ban Ki Moon is scheduled to deliver a speech at the memorial service. International Atomic Energy Agency Director General Yukiya Amano, a Japanese national, will also attend the service.
Among nuclear powers, France will send its charge d'affaires for the first time ever, while Russia will be represented by a first secretary at its embassy in Tokyo.
Pakistan will be represented by its consul general in Osaka and Israel by its ambassador to Japan for the second year in a row.
The annual service will begin at 8 am on August 6 as usual and last for 45 minutes, and will be held at the Peace Memorial Park.
The number of participants is expected to top last year's 50,000. Among them will be 41 representatives of bereaved families of people killed in the bombing.
The municipal government expects Prime Minister Naoto Kan, Foreign Minister Katsuya Okada and Health, Labor and Welfare Minister Akira Nagatsuma to represent the Japanese government, the officials said.