The United States and the EU on Monday imposed sanctions on top DR Congo officials after clashes with protesters against President Joseph Kabila in September left more than 50 people dead.

DR Congo — once ruled from Brussels as a Belgian colony — immediately slammed the EU move as an “illegal” throw-back to imperial days, warning it would take unspecified action against them.

Washington had previously targeted several senior figures close to the president and on Monday added Deputy Prime Minister Evariste Boshab and Kalev Mutondo, head of the national intelligence agency, for rights abuses.

“The Congolese government continues to undermine democratic processes in the DRC and to repress the political rights and freedoms of the Congolese people, putting the long-term stability and prosperity of the country at risk,” the US Treasury said in a statement.

European Union foreign ministers had made clear in October they would go ahead with sanctions if Kabila showed no sign of leaving office when his term ends on December 19.