China has been irritated by high-profile Czech delegations visiting Taiwan -- a self-ruled island that Beijing claims as its territory.

The Czech intelligence service, meanwhile, singled out China as a threat to security in its 2024 annual report.

"Detectives from the National Centre Against Terrorism, Extremism and Cybercrime detained a person suspected of working for Chinese intelligence services on Saturday," police said on social media.

The High Public Prosecutor's Office in Prague, supervising the case, did not respond immediately to AFP's questions.

The Denik N daily said the person was a Chinese national.

The Czech Republic, an EU and NATO member of 10.9 million, has angered Beijing as delegations including parliament speakers have visited Taiwan, and Taiwanese officials came to Prague several times.

China sees Taiwan as its territory and tries to keep it isolated on the world stage, preventing any sign of international legitimacy for the island.

It sees such visits as an infringement of the one-China policy which Prague officially pursues, just like the rest of the EU.

Last year, Taiwan accused Beijing's embassy staff of spying on vice president Hsiao Bi-khim and planning to ram her car during a visit to Prague in March 2024.

Czech military intelligence then confirmed that Hsiao was targeted by "persons legalised in diplomatic positions at the Chinese Embassy in Prague".

Last May, the Czech foreign minister summoned China's ambassador to Prague over a cyberattack targeting the ministry.

The ministry said an investigation into the attack "led to a high degree of certainty about the responsible actor", naming it as China-linked group APT31.