A Venezuelan man who was deported from California to El Salvador and held at one of the country's infamous prisons recounts his months in custody, recalling meager rations and the torture and beating of fellow inmates.

Venezuela says it is opening a formal investigation into several Salvadoran officials, including President Nayib Bukele, over the alleged abuse of Venezuelan migrants deported from the US.

Some of the Venezuelans detained in El Salvador's notorious Cecot prison have alleged physical assault, sexual abuse and torture.