New Delhi, July 2 -- The pilot who crashed a small plane into Beijing's tallest skyscraper was suffering from mental health issues and had written about suicide in his diary, according to Chinese authorities.

The 66-year-old pilot died in the incident that injured 13 people. He reportedly flew a light aircraft into the 528-metre (1,732-foot) CITIC Tower in Beijing's Central Business District on Friday at 5:55 pm (0955 GMT).

According to the official statement of the Chaoyang district government, the pilot, surnamed Liu, was divorced and lived alone in Beijing.

In his diary, the govt said, Liu made multiple references to 'ending his life' and "had long suffered from insomnia and anxiety". "This was an incident endangering public safety ...