Chinese hackers

Patel was recently informed by the bureau that Iranian hackers had managed to access at least some of Patel's communications. 

"These attacks have the potential to disrupt the critical lifeline of clean and safe drinking water, as well as impose significant costs on affected communities," the letter said.

It is the first time the Netherlands has publicly attributed cyber espionage activity to China, as tensions surrounding national security grow between Beijing and The Hague.