The US announced the decision as Venezuela struggles to restore electricity following four days of blackouts and a deepening political crisis.
"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."
The United States slapped sanctions on Venezuela's oil industry in January,and pledged further action on Wednesday.
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.
Russia and China support Venezuelan President Nicolas Maduro while the US and its allies recognise opposition leader Juan Guaido as interim president.
Lima Group of countries has met with US Vice President Mike Pence but rejected a military intervention.