Japan is considering contributing around $100 million to a United Nations-proposed fund to fight AIDS, which is spreading particularly rapidly in impoverished sub-Saharan Africa, government sources said Thursday.

The government will decide on the size of the contribution before a forthcoming annual summit of leaders from the Group of Eight major countries. Prime Minister Junichiro Koizumi is expected to unveil the figure at the summit, the sources said.

The AIDS issue is expected to be high on the agenda at the three-day G8 summit, which will open in the Italian port city of Genoa on July 20. The G8 comprises the United States, Canada, Britain, Germany, France, Italy, Japan and Russia.