"If the US go in,it'll be three days. If the Colombians go in,maybe a week,"said retired colonel José Machillanda.
The power blackout is the latest calamity to befall a country in seemingly perpetual crisis.
The nationwide power failure has intensified pressure on President Nicolas Maduro,who appeared in public on Saturday for the first time since the country plunged into darkness.
An electrical outage has left much of Venezuela without power in what authorities are decrying as an act of"sabotage."
Guaido tweeted that Venezuelans should monitor his official announcements and that he would provide details about meeting points for supporters
Juan Guaido,who is trying to build international pressure to oust President Nicolas Maduro,did not comment on the timing of his planned return to Venezuela
Juan Guaido defied a travel ban to go to Colombia. He is now visiting one South American country after another.
Lima Group of countries has met with US Vice President Mike Pence but rejected a military intervention.
Venezuela is in chaos as rival rulers face off with another. Other nations are weighing in too. How did it come to this?
President Nicolas Maduro just shrugged off the biggest challenge to his power since Juan Guaido declared himself interim leader. Now Guaido needs a Plan B.
US Vice President Mike Pence is set to announce"concrete steps"and"clear actions"to address the Venezuela crisis when he meets regional leaders.