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.

Venezuela Attorney General Tarek Saab said on Monday that his office will investigate El Salvador's President Nayib Bukele and two other officials for the alleged abuse of Venezuelans who were detained in the Central American country.