Venezuelan security forces fired tear gas at protesters chanting "We want food!" near Caracas' presidential palace on Thursday, the latest street violence in the crisis-hit OPEC nation.
Hundreds of angry Venezuelans heading towards Miraflores palace in downtown Caracas were met by National Guard troops and police who blocked a major road.
President Nicolas Maduro, under intense pressure over a worsening economic crisis in the South American nation of 30 million, had been scheduled to address a rally of indigenous groups nearby around the same time.
The protest spilled out of long lines at shops in the area, witnesses said, after some people tried to hijack a food truck.
"I've been here since eight in the morning. There's no more food in the shops and supermarkets," one woman told pro-opposition broadcaster Vivoplay. "We're hungry and tired."
The government accused opposition politicians of inciting the chaos but said security forces had the situation under control.
Despite their country having the world's biggest oil reserves, Venezuelans are suffering severe shortages of consumer goods ranging from milk to flour, soaring prices and a shrinking economy.
Maduro blames the fall in global oil prices and an "economic war" by his foes, whom he also accuses of seeking a coup.
"Every day, they bring out violent groups seeking violence in the streets," he said in a speech at the indigenous rally, which went ahead near Miraflores later in the day. "And every day, the people reject them and expel them."
Critics say Venezuela's economic chaos is the consequence of failed socialist policies for the last 17 years, especially price and currency controls.
The opposition wants a referendum this year to recall Maduro. Protests over shortages, power cuts and crime occur daily, and looting and lynchings are on the rise.
Several local journalists said they were robbed during Thursday's chaos in downtown Caracas.
The government's top economic official, Miguel Perez, acknowledged the hardships Venezuelans were undergoing but promised the situation would improve.
"We know this month has been really critical. It's been the month with the lowest supply of products. That's why families are anxious," he told local radio. "We guarantee things will improve in the next few weeks."