An aide to Donald Trump said on Monday the FBI is investigating threatening tweets to the U.S. Republican presidential candidate purported to have originated from Joaquin "El Chapo" Guzman, a notorious Mexican drug lord who escaped from prison on Saturday.

Reuters could not confirm the authenticity of the Twitter accounts from which the threats were allegedly made.

Trump, a real estate billionaire who has generated controversy by saying many illegal immigrants from Mexico are criminals and rapists, said in a statement on Sunday that "corrupt Mexican officials" had let Guzman escape.