Venezuelan President Nicolas Maduro and his challenger Juan Guaido on Monday vied for the army’s support in their power struggle.

Pro-government Defence Minister Vladimir Padrino vowed to defend the country against “any aggression,” while Guaido said it would only take “a political decision” by the military to oust Maduro.

The army has so far sided with Maduro. Guaido, who presides over the opposition-dominated National Assembly and declared himself interim president last week, has promised an amnesty to soldiers who support fresh elections and a political transition.

“We would be unworthy of wearing this uniform and these symbols of the fatherland, if we did not face up to this difficult moment of an incontestable threat against the fatherland,” Padrino said before marching with top army brass through the Tiuna fortress in Caracas.

Maduro accuses the United States of having instigated what he describes as Guaido’s attempt at a “coup” against his government.

“In the face of any aggression, of any nature or intensity, we shall defend Venezuela,” Padrino vowed.

Guaido, meanwhile, told the Colombian daily El Tiempo that it would only take “a political decision” by the army to topple Maduro.

Asked if soldiers will comply, Guaido replied: “Yes, I believe that. And we are working to facilitate that route.”

At the weekend, Guaido tried to bring the army to his side by publishing the amnesty law approved by the National Assembly.

In comments to the broadcaster Telesur during the march, Padrino called the law “a document of manipulation” and said the army did not believe in it.