USA special envoy for Venezuela Elliott Abrams said on Friday that Washington would continue "appropriate actions" against Maduro, including restricting travel visas for dozens with links to the embattled president.
Maduro has called the US -backed humanitarian aid effort a veiled invasion meant to push him from power, and has insisted that there is no crisis in the country.
He promised that Russian Federation would maintain its support to the Venezuelan government with aid supplies as the Latin American country faces economic meltdown with hyperinflation and a lack of basic products.
"I'm announcing my return home from Ecuador", Guaido said after meeting its president, Lenin Moreno.
The young opposition leader already has the backing of the United States, as well as numerous countries in Latin America and Europe.
U.S. President Donald Trump has said all options are on the table in dealing with Venezuela's crisis, though Abrams this week stressed the word "peaceful".
Self-proclaimed interim president of Venezuela, Juan Guaido, recongnized as rightful leader by most of the western countries, has visited Argentina and Paraguay on Friday to ramp up American support for the transition government for crisis-hitten nation.
Pinera, a Chilean billionaire elected president for the second time in 2017, is a key supporter of Guaido, and joined the Venezuelan opposition leader in Cucuta, Colombia last weekend in a failed attempt to send global humanitarian aid into Venezuela.
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Trump also tweeted about Kim, calling the North Korean leader his "friend" and describing the country's potential as "AWESOME". Trump critics said he squandered critical US leverage before the North had taken any concrete steps toward denuclearization.
Venezuelan President Nicolas Maduro said earlier this week that Guaido must face trial after his return for breaking the travel ban.
Russian Federation and China have vetoed a U.S. push for the United Nations Security Council to call for free and fair presidential elections in Venezuela and unhindered aid access.
Russia's Foreign Minister Sergei Lavrov conveyed President Vladimir Putin's words of support for and solidarity with Maduro Friday during talks with visiting Venezuelan Vice President Delcy Rodriguez.
The United States said in January sanctions against PDVSA meant to make oil revenues available only to Guaido, who Washington considers Venezuela's interim president.
Guaido has been recognized by the United States and other countries as president in opposition to Nicolas Maduro's regime.
Those sanctioned include Venezuelan special forces commanders and members of the national police.
In a second tweet Guaido said he would provide an account of his tour and announce the opposition's "next actions" on social networks at 8:30 pm (0030 GMT Monday).
Guaido is still in Colombia, and Abrams warned of a "very large reaction" if he were to be harmed by Venezuelan authorities upon his eventual return.