- Video report by ITV News Correspondent Dan Rivers
Venezuelan President Nicolas Maduro has said he will never surrender and has vowed to defend his country's independence with his life if necessary.
Mr Maduro's comments came as two protesters were killed and another 18 injured during clashes between soldiers and residents of the southeastern town of Santa Elena de Uairen, near the border with Brazil.
In the capital, Caracas, Mr Maduro addressed thousands of cheering supporters dressed in red shirts, the color of Venezuela's socialist party.
Also on Saturday, five soldiers from the Venezuelan National Guard deserted their border posts in a bid to allow aid into the country which is suffering a political and economic crisis.
The five men said they recognised opposition leader Juan Guaido as their commander-in-chief.
Despite the defections, the majority of forces remain loyal to the President, and have blocked aid convoys at the country's borders with Brazil and Colombia.
As protesters attempted to clear the blockaded border in the town of Urena, troops loyal to Mr Maduro fired tear gas and pellets at them.
At the border with Colombia, Venezuelans rescued emergency aid boxes from burning trucks stalled on a bridge connecting the two countries.
Mr Guaido is attempting to get aid into the country as Venezuela's inflation rate has seen prices soar in recent years, leaving many struggling to afford basic items such as food, toiletries and medicine, in the world's most oil-rich nation.
The self-declared interim president - who has promised to overthrow Mr Maduro and hold new elections to restore democracy - argues aid is desperately needed and could save thousands of lives.
However, President Nicolas Maduro denies a humanitarian crisis exists and has ordered the closing of his country's borders to block Mr Guaido's efforts, which he says are part of a US-led coup and has branded him a puppet of the White House.
Also on Saturday, Mr Maduro has broken diplomatic relations with Colombia, likely over the stockpiling of aid intended for Venezuela in the country.
Aid has become the centre-piece of the standoff between the two men.
Two trucks carrying humanitarian aid from Brazil are stuck at the Venezuelan border, contradicting earlier reports by Mr Guaido that they had managed to break through a police blockade and enter the country.
The lorries remain stationed in the arid expanse separating the Brazilian city of Pacaraima from the Venezuela city of Santa Elena de Uairen.
Meanwhile, lorries carrying aid also remain stuck at the border with Colombia.
Away from the border, thousands of protesters have flooded the streets of Caracas in rival demonstrations.
In the capital, Maduro loyalists marched by the thousands to the city center to the sounds of brass bands, while others rode motorcycles.
Meanwhile, opposition supporters converged on a Caracas military base, urging soldiers to join their fight.
Many were dressed in the colors of Venezuela's flag and some came in costume as Captain America characters.
The opposition gathering in the capital was much smaller than that held by government supporters, but many Venezuelans who want Maduro to step down turned out en masse near the country's border crossings.