Japanese Foreign Minister Taro Kono is suffering from ill health and has been unable to carry out his official duties while he recuperates, public broadcaster NHK said Friday.

According to the Foreign Ministry, Kono was diagnosed on Thursday with a condition known as pyelonephritis, which is inflammation of the kidneys often due to a bacterial infection.

The condition can cause a high fever and nausea and can lead to sepsis and, in more extreme cases, kidney failure.

On Wednesday morning, the ministry said Kono, 56, was found to have had a high fever and has been recuperating in Tokyo and is scheduled to have further medical tests on Friday at a hospital.

A senior official from the Foreign Ministry apologized to the directors of the Upper House budget committee on Kono's behalf for his absence.

The official asked whether Kono's deputies could take part in the deliberations in the upper house on Friday, adding that disruptions to the Diet caused by the absence of the minister would be kept to a minimum.

Kono's ill health on Wednesday caused the cancellation of a scheduled session of the Upper House foreign affairs and defense committee.

On Friday, the committee session went ahead with State Minister for Foreign Affairs Masahisa Sato sitting in for Kono.