Updated

Prosecutors at Cambodia's Khmer Rouge tribunal say the trial sends a strong message to the world that massive human rights violations will not go unpunished.

Chea Leang led closing arguments for the prosecution Thursday in the case against two surviving leaders of the communist regime under which an estimated 1.7 million people died.

Nuon Chea, the regime's chief ideologist, and Khieu Samphan, its head of state, both in their 80s, are charged with genocide and crimes against humanity.

The Khmer Rouge, in power from 1975-79, emptied the country's cities, forcing Cambodians into backbreaking work in rural cooperatives and executing anyone suspected of dissent. Executions, death by starvation, torture, lack of medical care and overwork were rampant.