Chinese state-backed cyber spies gained access to a Dutch military network last year, the intelligence agency MIVD said last month, calling it part of a trend of Chinese political espionage against the Netherlands and its allies.

It was the first time the Dutch publicly attributed cyberespionage to China, as national security tensions grow between the two countries. They are also in a confrontation over restrictions of exports of high-tech semiconductor equipment made by Dutch giant ASML to China.

Beijing routinely denies allegations of cyberespionage and says it opposes all forms of cyberattack.

U.S. and British officials on Monday filed charges, imposed sanctions and accused Beijing of a sweeping cyberespionage campaign that allegedly hit millions of people including lawmakers, academics and journalists, and companies including defence contractors.

"Of course we discuss all difficult topics," including cyberattacks, Rutte told reporters after the talks in Beijing.

"Of course this has been very openly attributed to China by the Netherlands. It was an attack on the Dutch Ministry of Defence that our MIVD has identified and also attributed to China. So yes, of course, I discussed it."

Tensions between Beijing and Western powers over issues related to cyber espionage have been rising as Western intelligence agencies increasingly sound the alarm on Chinese state-backed hacking activity. China has also begun in recent years to call out alleged Western hacking operations.

(Reporting by Ryan Woo and Ella Cao; Additional reporting by Anthony Deutsch in Amsterdam and James Pearson in London; Editing by Alex Richardson)