A former executive director of Amnesty International Japan has sued the human rights organization for ¥5 million ($47,500), claiming unfair dismissal after he was diagnosed with depression that stemmed from being forced to give reports in Japanese, sources familiar with the case said Tuesday.

According to the complaint filed with the Tokyo District Court, Taro O'Sullivan said the organization hired him with the knowledge that he could speak Japanese at a conversational level but could barely read or write it.

The 62-year-old American is also seeking to have his dismissal overturned and has filed for damages against the Tokyo-based organization and Kaori Shoji, a professor at Gakushuin University in Tokyo who was the organization's chair at the time.