Prime Minister Shigeru Ishiba has told Microsoft co-founder Bill Gates that Japan will donate $550 million over five years to "Gavi, the Vaccine Alliance," which promotes immunization in developing countries.

Ishiba presented the plan at a meeting with Gates, who heads the Gates Foundation, at the prime minister's office in Tokyo on Tuesday, according to Tetsuo Saito, leader of Komeito, the coalition partner of Ishiba's ruling Liberal Democratic Party. Saito was also present at the meeting.

The prime minister will announce the pledge at the Ninth Tokyo International Conference on African Development (TICAD 9), set to begin in Yokohama on Wednesday. The conference will run for three days.

Gates thanked Japan for the donation and reaffirmed his commitment to strengthening cooperation with the country, according to Saito.

Gavi was launched in 2000 through the partnership between public institutions such as the World Health Organization and private organizations including the Gates Foundation.