LONDON (REUTERS) - Britain's government is deeply concerned about China's legislation on national security for Hong Kong, which risks undermining the principle of one nation, two systems, a spokesman for Prime Minister Boris Johnson said on Thursday (May 28).

"We are deeply concerned about China's legislation relating to national security ... We have been very clear that the security legislation risks undermining the principle of one nation, two systems," the spokesman said, adding that foreign minister Dominic Raab spoke to US Secretary of State Mike Pompeo late on Wednesday.

"The steps taken by the Chinese government place the joint declaration under direct threat," he added, referring to the 1984 agreement between Britain and China that Hong Kong's high degree of autonomy would remain unchanged for 50 years.