Beijing has warned new Hong Kong lawmakers not to back independence for the semi-autonomous city after young anti-China activists won seats for the first time in key weekend elections.

Sunday’s vote saw activists pushing for more autonomy from Beijing secure a crucial foothold in the city’s Legislative Council (LegCo), as fears grow that China is tightening its grip.

It was the first major poll since pro-democracy rallies in 2014 failed to win concessions on political reform from Beijing.

Some student protest leaders were among those winning seats in the landmark vote. Five candidates advocating independence or self-determination for Hong Kong are to sit in the 70-seat assembly.

In a statement late Monday, China said that it would not tolerate any talk of independence “inside or outside” the legislature.

“We firmly oppose any activity relating to Hong Kong independence in any form, inside or outside the Legislative Council, and firmly support the Hong Kong government to impose punishment in accordance with the law,” state news agency Xinhua cited a spokesperson of the Hong Kong and Macau Affairs Office of the State Council — China’s cabinet — as saying.