A Taiwan court has convicted a former presidential aide of spying for China and three others who were also employed by the ruling Democratic Progressive Party (DPP).

One of the men worked in the office of then Foreign Minister Joseph Wu who now serves as the national security chief.

The court handed the men jail terms of between four to 10 years for leaking state secrets. The ruling said the espionage was carried out “over a very long period of time” and involved sharing “important diplomatic intelligence”.

Beijing claims democratically-governed Taiwan as its own, and the two have been spying on each other for decades. But Taipei claims Chinese espionage has intensified in recent years.

Of the four men sentenced on Thursday, Huang Chu-jung, a former assistant to a Taipei councillor, received the longest jail time: 10 years. Prosecutors had initially sought sentences of up to 18 years.

All four of them were charged in June, a month after they were expelled from the DPP.

[…]