Venezuela's Defense Minister Vladimir Padrino on Tuesday reaffirmed the military's "absolute loyalty" to President Nicolas Maduro, amid an on-going dispute over the country's contested presidential election results.

The comments came after opposition candidate Edmundo Gonzalez and leader Maria Corina Machado urged members of the armed forces "to stand at the side of the people," in a letter published on Monday.

"We ratify our absolute loyalty to citizen Nicolás Maduro Moros," Padrino said during a broadcast by state television, where he was flanked by the top brass of the military and the police.

These "fatuous and irrational calls seek to break our unity and institutionality, but they will never achieve it," Padrino added.

The opposition maintain Gonzalez won more than 6 million votes, compared to 2.7 million won by Maduro, and have published online a copy of ballots from 30,000 voting machines.

The government says it also has copies of the ballots but has not yet published them, nor has the country's electoral authority, whose website has been down since the early hours of Monday, July 29.

After Gonzalez and Machado published the letter, attorney general Tarek Saab announced a criminal probe against both of them for inciting members of the military and the police to break the law.

"Fear is not going to paralyze us, we are going to overcome it as we have done until now and we will not leave the streets," Machado said in an audio message posted on X on Tuesday.

The Venezuelan president's assertion that he won a third term in the July 28 vote triggered protests and accusations of fraud, with opposition leaders insisting Gonzalez won and that Maduro should stand down.