The power struggle between Maduro and Guaido has intensified the sense of crisis in Venezuela, which suffered its worst blackouts earlier this month.
The United States has led more than 50 countries in recognizing Guaido as Venezuelan leader, calling Maduro's May re-election illegitimate.
Rosales was given a high-profile reception in the Trump administration's latest bid to boost Guaido, who is under severe pressure from Moscow-backed Maduro.
Trump administration says Indian private companies have stopped importing oil from sanctions-hit Venezuela
Venezuela is the third largest supplier of oil to India which is the world's third-biggest oil consumer.
The US has already imposed sanctions designed to choke off Venezuelan oil sales, the lifeblood of the leftist government in Caracas.
Earlier in the day, the Treasury sanctioned a Russia-based bank attempting to circumvent US sanctions on Venezuela's state-owned oil company PDVSA.
The sanctions targeted Moscow-based Evrofinance Mosnarbank, which when founded in 2011 was 50 per cent-owned by leading Russian banks and 49-per cent owned by Venezuela's National Development Fund.
Four people were killed in the melee as Maduro's forces prevented the 178 metric tonnes of rice, beans and other food from crossing into the country from Colombia.
Venezuelan President Nicolas Maduro later shut down four bridges that cross the frontier into Colombia.
Vice President Mike Pence travels Monday to the Colombian capital to meet with members of a regional coalition and Venezuelan opposition leader Juan Guaido to discuss the next steps aimed at ousting M
The email with the letter included plane tickets for Acosta and his son to fly back to Venezuela on Sunday.
Maduro said that he holds out hope of meeting the U.S. president soon to resolve a crisis triggered by America's recognition of opponent Juan Guaido as Venezuela's rightful leader.
Venezuela is plagued by hyperinflation and major shortages of basic goods, and two men -- opposition leader Juan Guaido and President Nicolas Maduro -- are vying for control of the country.
While most European countries have also recognised Guaido as the interim President, countries like Russia, China, Turkey, amongst others, have slammed foreign interference in Venezuela
Already recognised by the United States, Canada, Australia and several Latin American countries, Guaido is trying to force the socialist leader from power so he can set up a transitional government.