"We are prepared to take further action if the government of Venezuela persists on its path to impose authoritarian rule on the Venezuelan people", Trump said.
In his speech, Trump called the situation in Venezuela "completely unacceptable" and called for help so the country's people can "regain their freedom, recover their country and restore their democracy".
At least 125 people have been killed in four months of protests against the Maduro government, which has resisted calls to bring forward the presidential election and instead set up a pro-Maduro legislative superbody called a Constituent Assembly that has overruled the country's opposition-led Congress.
President Donald Trump said on Monday he wanted democracy restored soon in Venezuela and warned that the United States might take additional measures to apply pressure on the oil-producing nation.
Differences over ethanol trade, open-skies aviation and illegal drug production, and even North Korea, could crop up during the discussion, but the top issue will be the Venezuelan crisis, Latin American and White House officials said.
"We have told Trump that military intervention is not on the agenda for any Latin American country", Santos told Bloomberg.
Santos and the other Latin American presidents have been trying to step up diplomatic pressure on their Venezuelan counterpart Nicolas Maduro for months.
"This racist and supremacist theory which he's exposing, this return to the Cold War, for a moment we didn't know if we were listening to president Reagan in 1982 or President Trump in 2017", Foreign Minister Jorge Arreaza said.
"I urge every country here to prepare to do more to address this incredible and serious crisis. Their country is collapsing", he said.
In attendance during the talk were Brazilian President Michel Temer, Colombian President Juan Manuel Santos, President of Panama Juan Carlos Varela, and Vice President of Argentina Gabriela Michetti.
More recently, a constitutional assembly wholly made up of government loyalists has been installed and proceeded to go after Maduro's political opponents. "We want it to happen very soon".