Canceling the debts of African countries "is not a matter of charity but a matter of justice" to efficiently eradicate extreme poverty on the continent, Irish rock star Bono said Thursday.

Bono, lead singer of the band U2, made the remark in a speech at the fourth Tokyo International Conference on African Development held in Yokohama.

He said debt relief by developed countries genuinely works, noting that 29 million African children were able to restart school in the last 12 years because of efforts to annul public debt in Africa.

The antipoverty activist had released a statement Wednesday disapproving of some of Prime Minister Yasuo Fukuda's pledges on African aid.

Fukuda promised during his opening keynote speech of TICAD that Japan will double its annual net official development assistance to Africa to ¥1.8 billion by 2012. However, in a press release, Bono called the promise "misleading" since the doubling applies only to Japan's bilateral ODA to African nations and not to its multilateral ODA.

The rocker, who was introduced as a figure "admired by youth all over the world" by former Prime Minister Yoshiro Mori, did not pass judgment on the issue Thursday.

Instead, he urged Japan to show leadership in July's Group of Eight summit in Hokkaido and spread its understanding of successful development aid acquired in assisting Southeast Asian countries.