WASHINGTON (Reuters) - The United States called on China on Monday to release four human rights lawyers and activists who were convicted of subversion last week.

Attorneys Zhou Shifeng and Gou Hongguo and activists Hu Shigen and Zhai Yanmin were given sentences ranging from three to 7-1/2 years in prison by a court in China’s northeastern city of Tianjin.

“We urge Chinese authorities to release the lawyers and rights defenders who are imprisoned or in detention, including those already sentenced,” State Department spokeswoman Elizabeth Trudeau said in a statement.

The four sentenced last week are among dozens of people linked to a Beijing law firm who have been swept up in a crackdown on dissidents since July last year as President Xi Jinping’s administration has tightened control, citing a need to boost national security and stability.

“More than a dozen other attorneys and activists detained on and around July 9, 2015, including Li Heping, remain in pretrial detention without access to their families or to legal counsel of their own choosing,” the State Department statement said.

“We call for an immediate end to the cases brought against them and to restrictions on their freedom of movement and professional activities,” it said.