Venezuelan doctors have called on the military to unblock the Tienditas International Bridge so humanitarian aid can reenter the country.
They protested on the Colombian side of the border to avoid repercussions at a time of huge political tension.
Opposition leader Juan Guaidó has proclaimed himself interim president after claiming Nicholas Maduro's presidency is illegitimate.
The US has imposed harsh sanctions on the country's oil exports.
Jens Laerke, a spokesman for the UN Office for the Coordination of Humanitarian Affairs, is committed to delivering aid.
India begins voting in second phase of giant election
Northern Gaza still heading toward famine, says deputy WFP chief
Blinken meets Chinese counterpart Wang Yi in Beijing
Harvey Weinstein's conviction overturned by New York court
North Korea's Kim Jong-Un inspects test-firing of multiple launch rockets
