Japan has lodged a protest against a U.N. working group that denounced its past detention of former Nissan Motor Co. boss Carlos Ghosn in Tokyo over financial misconduct allegations as "arbitrary," sources close to the matter said Monday.

A recent report compiled by the U.N. Working Group on Arbitrary Detention asserts that the conduct of Tokyo prosecutors was arbitrary regarding the detaining of Ghosn ahead of his expected trial.

Former Nissan Motor Co. Chairman Carlos Ghosn speaks in a pool interview with Japanese media organizations in Beirut on Jan. 10, 2020. (Kyodo) ==Kyodo

The Japanese Foreign Ministry lodged the protest on Friday, saying the U.N. panel's view was not based on a proper understanding of the Japanese legal system, the sources said.

The panel's report backs up Ghosn's claim that he was detained for a long period of time under severe conditions, and called for the Japanese government to launch "a full and independent investigation" of the matter and "take appropriate measures against those responsible for the violation of his rights."

The report also indicated the need to compensate the former Nissan CEO for damages suffered.

The report is not legally binding.

In the protest, the Foreign Ministry says that Ghosn's escape from Japan while awaiting trial is an unforgivable act under the legal system of any country, and maintains that the panel misunderstands some aspects of the situation.

The ministry also argues that proper criminal procedures were fully observed with respect to Ghosn's rights, according to the sources.

Ghosn, initially arrested by Tokyo prosecutors in 2018, was released on bail in April 2019. He jumped bail and fled to Lebanon, where he spent his childhood, via Turkey late that year. Japan does not have an extradition treaty with Lebanon.

Ghosn, who headed Nissan for nearly two decades, faced trial in Japan over allegations that he misused company funds and understated his remuneration by billions of yen over a period of multiple years.

He has denied the allegations and said he fled Japan to escape what he called a "rigged" justice system.