(CNN) Five South American countries and Canada want Venezuela placed under investigation as a humanitarian crisis continues to roil the country.

The leaders of Argentina, Chile, Colombia, Paraguay, Peru and Canada on Wednesday signed a joint statement addressed to the president of the International Criminal Court asking for a probe into possible crimes against humanity in Venezuela.

The alleged crimes, dating to 2014, include extrajudicial murder, torture and the arbitrary detention of political opponents and anti-government protesters.

The request, made at UN headquarters in New York as the UN General Assembly meets this week, is the first time ICC member governments have sought an investigation of alleged crimes that took place entirely on the territory of another country, Human Rights Watch said.

This multilateral move is the latest blow to Venezuelan President Nicolas Maduro, after the United States this week slapped sanctions on his wife and three other members of his inner circle in an effort to get Maduro to weaken his grip on the military and the government.