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's attorney general's office said on Monday that it has opened an investigation into El Salvador's President Nayib Bukele for alleged mistreatment and human rights violations against Venezuelan migrants.