Japanese Foreign Minister Taro Kono has canceled his official duties on Friday because of poor health.
The Foreign Ministry says that Kono was diagnosed on Thursday with pyelonephritis, a condition triggered by a bacterial infection of the kidneys.
The ministry says Kono developed a fever on Wednesday morning and has been resting in Tokyo.
A high-ranking ministry official apologized to the directors of the Upper House budget committee for Kono's absence.
He explained that Kono still has a fever and will undergo a further examination at a hospital on Friday.
He asked the directors to allow one of Kono's deputies to take part in the deliberations. He said the minister's condition will be carefully monitored to avoid causing any more trouble for the Diet.
The Upper House foreign affairs and defense committee cancelled a scheduled session on Wednesday, due to Kono's illness. But the committee convened on Friday with State Minister for Foreign Affairs Masahisa Sato taking Kono's place.