An international rights group says European countries share responsibility for hundreds of migrants intercepted by Libyan authorities and sent to "squalid detention centers."

Amnesty International said Wednesday that in the past two months at least 2,600 migrants have been transferred to such centers, where it says they face torture and extortion.

European countries have backed Libyan efforts to stem the tide of migrants fleeing war and poverty in Africa and the Middle East. Amnesty says that makes the Europeans responsible for abuses carried out by Libyan forces.

Libya was plunged into chaos after a 2011 uprising toppled and killed Moammar Gadhafi. Today the country is ruled by two rival governments, each of which relies on a patchwork of local militias.