NHK has released its investigative report on inappropriate comments made during a Chinese-language radio news bulletin last month by an outside employee of Chinese nationality.

NHK President Inaba Nobuo apologized at a news conference on Tuesday.

Inaba said: "This can be described as a case of "broadcast hijacking." It is an extremely serious situation that violated NHK's own international program standards, and NHK failed to fulfill its responsibility as stipulated by the Broadcasting Act, which we take very seriously. We once again offer our profound apologies."

He revealed that four executives, including himself, will voluntarily return 50 percent of their executive compensation for one month, and that a senior director in charge of international broadcasting will step down.

During the broadcast on August 19, the 48-year-old outsourced employee made unscripted remarks that were inconsistent with the Japanese government's official views, regarding issues such as the territorial sovereignty of the Senkaku Islands in Okinawa Prefecture.

The investigative report says other staffers monitoring the broadcast realized the remarks were being made, but they did not take steps such as cutting the audio. They have explained they couldn't respond because it happened so suddenly.

The report also says the outside employee had conveyed to NHK staff his worries and concerns about how Chinese authorities would respond to the news reports that he was reading, and his dissatisfaction with his take-home pay.

The report says if such remarks and claims had been noted, appropriate steps could have been taken.

The report adds that measures taken after the broadcast, such as a correction of what was said and timely explanation to viewers, listeners and the general public, were insufficient. The report says there wasn't enough sense of crisis.

To take responsibility, President Inaba Nobuo, Executive Vice President Inoue Tatsuhiko, Executive Director Yamana Hiroo, and Senior Director Nakajima Taichi will voluntarily return 50 percent of their executive compensation for one month.

The Senior Director in charge of the international broadcast service, Sobata Kenji, will resign as of Tuesday.

Disciplinary action was taken against five others, including the head of the NHK WORLD-JAPAN Department, whose wage was cut.

Two executives of NHK Global Media Services, which had signed a contract with the Chinese employee, will voluntarily return 30 percent of their executive compensation for one month.

NHK says it will switch to pre-recording international radio broadcasts and consider introducing AI audio. It will also work more closely with the domestic broadcast service, which has a solid editing system, to thoroughly implement checks and restraints.

By doing so, it will aim to bolster governance regarding its international broadcasts and regain public trust.