Speaking in the Commons on Tuesday, U.K. Security Minister Dan Jarvis said the latest assessment showed how China “is attempting to recruit and cultivate individuals with access to sensitive information about parliament and the U.K. government.”

He said such work is being carried by a group of Chinese intelligence officers “often masked through the use of cover companies or external headhunters.”

“China has a low threshold for what information is considered to be of value, and will gather individual pieces of information to build a wider picture,” he warned in a House of Commons statement.

In a bid to get on the front foot over the issue, Jarvis on Tuesday announced a new “counter political interference and espionage action plan.” Measures include tougher risk assessment rules for recipients of donations, and enhanced enforcement powers for the Electoral Commission, the U.K.’s elections watchdog.

Security campaigns led by the U.K. parliamentary authorities will also take place, including tailored briefings for Britain’s devolved governments, political parties, and all candidates taking part in devolved and local elections next May.

“This activity involves a covert and calculated attempt by a foreign power to interfere with our sovereign affairs in favor of its own interests, and this government will not tolerate it,” Jarvis warned.

The guidance follows a bitter political row in the U.K. over Chinese interference in British politics.

British prosecutors this year dropped charges against two men accused of spying for China, one of whom previously worked in parliament. The Palace of Westminster is also contemplating tightening parliamentary access for Chinese visitors.