Venezuelan opposition leader Juan Guaido is expected to announce Sunday when humanitarian aid will be delivered to the crisis-ridden country.
Guaido told supporters Saturday the opposition would start collecting humanitarian aid in Brazil, Colombia and an unnamed Caribbean island and called on the military to allow the aid into the country.
The United States has said it would transport aid to Venezuela at Guaido's request. President Nicolas Maduro has refused to accept aid because he believes it opens the way for a U.S.-led military intervention.
WATCH: VOA Interviews Juan Guaidó
Two military leaders and an ambassador defected Saturday from the government of President Nicolas Maduro and instead recognized Guaido as the acting president.
Early Saturday, General Francisco Yanez called on other members of the military to defect as he announced his own defection in a social media video. He rejected Maduro's "dictatorial" authority and recognized Guaido as the acting president.
Major General Jorge Oropeza, former air force general commander, said later Saturday that he also recognized Guaido as acting president.
Top military leaders have helped Maduro survive mass demonstrations in recent years by jailing activists and repressing opposition protestors.
Guaido said in an interview with VOA Noticias he has offered "amnesty and guarantees" to high ranking military officials as part of a broader effort to get "this usurpation to end.
It remains unclear how much military support there is for Guaido.
Jonathan Velasco, Venezuela's ambassador in Iraq, also joined the defectors Saturday.
Supporters of opposition leader Guaido and President Maduro participated in rival demonstrations in Caracas Saturday.
Thousands of Guaido's supporters, carrying flags and blowing horns, converged on a handful of locations around Caracas in support of his call for early elections and the establishment of a transitional government amid mounting global pressure for Maduro to step down. Guaido arrived at one of the rallies with his wife, Fabiana, and was quickly surrounded by exuberant supporters.
Pro-Maduro demonstrators took to the streets on the western side of Caracas to celebrate the 20th anniversary of the Bolivarian revolution that led to the rise of socialist Hugo Chavez, Maduro's deceased predecessor. Maduro addressed the crowd, the first time he has appeared at a public rally since August 4.
Maduro called for parliamentary elections earlier than planned, repeated he is the country's legitimate president and told the crowd, "I am very ashamed to see this group of opposition coup perpetrators" take orders from Washington.
The demonstrations mark the second week of heightened tensions in Venezuela and come before a Sunday deadline set by major European countries for Maduro to call snap elections. Britain, France, Germany and Spain have said they will follow the U.S. in recognizing National Assembly Speaker Guaido as Venezuela's interim president if Maduro does not order new elections by Sunday.
Guaido declared himself interim president last week, a move that was supported by some two dozen countries. Guaido said during the VOA interview he would order new elections "when we achieve the capacity to convene elections." First, Guaido said, "we have to achieve the necessary force in order for this usurpation to end."
Guaido has rejected offers from Mexico's and Uruguay's presidents to negotiate with Maduro. Guaido told them in a letter that "to be neutral is to be on the side of the regime that has condemned hundreds of thousands of human beings to misery, hunger and exile, including death."
Maduro has presided over a Venezuelan economic collapse that has resulted in chronic shortages of food and medicine. He blames the U.S. for supporting what he calls a coup to remove him from power and exploit Venezuela's vast oil reserves.
U.S. Vice President Mike Pence met Friday with exiled Venezuelans in the southeastern U.S. city of Miami. Pence reassured them the U.S. would continue efforts to oust Maduro from office.
"This is no time for dialogue," Pence said. "It is time to end the Maduro regime."