Beijing, China - A former engineer has been sentenced to death in China after being accused of acting as a spy and leaking state secrets to a foreign power, Chinese authorities announced on Wednesday.

The man, surnamed Liu, "secretly copied, duplicated, and sold a large volume of state secrets to a foreign espionage and intelligence agency", China's Ministry of State Security said in a post to its official WeChat account.

Liu worked as an assistant engineer at a research institute and resigned after believing that he had been treated unfairly, the ministry said. His full identity or the name of the institute have not been revealed.

Before leaving his position, Chinese authorities allege that he "secretly copied and retained a large quantity of classified materials he had handled, intending to use them later for retaliation or blackmail."

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Liu went on to allegedly borrow money for high-risk investments, which then resulting in spiralling losses. He also stands accused of making illegal credit card cash withdrawals.

The Global Times reported that he then began plotting to sell the intelligence to an unnamed "foreign" actor in an attempt to get out of his debt.

Liu reached a deal to sell the information for an "exceptionally low cost," but the deal was a trap set by China's foreign intelligence agency. As a result, he was arrested and charged.

After allegedly confessing to his crimes, Liu was convicted of espionage and illegally providing state secrets. He was sentenced to death with lifelong deprivation of political rights.