The United States will begin the process of withdrawing special trade benefits for Hong Kong because of the Chinese government’s imposition of a new security law in the semi-autonomous city.

Tensions over Hong Kong have been increasing for more than a year as China has cracked down on protesters and sought to exert more control over the former British territory.

US President Donald Trump said the administration would begin eliminating the “full range” of agreements that had given Hong Kong a relationship with Washington that mainland China lacked, including on trade and extradition.

He said the State Department would begin warning US citizens of the threat of surveillance and arrest when visiting the city.

The president also said the US would be suspending entry of certain Chinese citizens.

He did not provide specifics, but officials said this week that the administration was considering expelling thousands of Chinese graduate students enrolled at US universities.