Venezuelan military officers blocked a bridge on the border with Colombia ahead of an anticipated humanitarian aid shipment Tuesday, as opposition leader Juan Guaido stepped up his challenge to President Nicolas Maduro's authority.
The opposition-dominated National Assembly had earlier warned the armed forces, which make up much of Maduro's power base, not to cross a "red line" by blocking aid.
Guaido, who proclaimed himself acting president on January 23 -- sparking an international crisis -- claims that up to 300,000 people face death if the aid is not delivered.
"You know there's a red line, you know well there's a limit, you know that medicines, food and medical supplies are that limit," lawmaker Miguel Pizarro said in a message to the military.
Maduro, though, said humanitarian aid would be the forerunner of a US-led invasion, insisting that "no one will enter, not one invading soldier."
In his State of the Union address Tuesday night, President Donald Trump reaffirmed US support for Guaido, saying "we stand with the Venezuelan people in their noble quest for freedom."
He thanked his EU supporters "for supporting all Venezuelans in this struggle we undertake to rescue our nation's democracy, freedom and justice."
But key Maduro ally Russia slammed what it called interference in the oil-rich but now poor Latin American country, saying it was an attempt to "legitimize usurped power."
Turkey's President Recep Tayyip Erdogan accused the EU of trying to "topple the government by violence and ruse," while berating the US for treating Venezuela like "one of your states."
The National Assembly said the military must decide whether it is on the side of the people or "the problem."
His fledgling alternative administration will hold talks in Washington February 14 on responding to "the largest hemispheric humanitarian crisis in modern history."
"If they want to help, then end the blockade and the sanctions."
Eurasia said US oil sanctions are "set to have a broad impact" with the government facing "the prospect of running out of gasoline, which could serve as another social catalyst."
Maduro has flatly rejected demands for new elections, telling Spanish television he would not "cave in to pressure."