US Secretary of State Mike Pompeo met with Hong Kong pro-democracy leader Martin Lee on Thursday, the State Department said, as Hong Kong activists seek to derail a proposed extradition law pushed by Beijing.

"Secretary Pompeo expressed concern about the Hong Kong government's proposed amendments to the Fugitive Ordinance law, which threaten Hong Kong's rule of law," the department said in a statement.

Lee founded the first pro-democracy party in Hong Kong in 1990 and has been a prominent voice calling for civil liberties for the city's residents.

Hong Kong lawmakers loyal to Beijing are pushing to enact a law that would allow people accused of a crime, including foreigners, to be extradited from the city to countries without formal extradition agreements, including mainland China.

Democracy activists fear the legislation would erode rights and legal protections in the former British colony that were guaranteed under the Basic Law when it returned to Chinese rule in 1997.

More than 130,000 people marched against the proposed legislation several weeks ago in one of the biggest protests since the Umbrella pro-democracy movement in 2014.

Pompeo "also expressed support for Hong Kong’s longstanding protections of human rights, fundamental freedoms, and democratic values, which are guaranteed under the Basic Law," the State Department said.