Turnout from 120-nation Cold War-era bloc has paled in comparison to past meetings with about 10 heads of state showing.
Venezuelan bus drivers have caused traffic chaos in Caracas by parking their buses in the street, protesting against the country’s economic crisis.
Hundreds of drivers joined the strike on Wednesday, demanding better pay, more security against violent crime and spare parts for their buses.
Tyres, car batteries and motor oil are on a long list of goods that have disappeared in the shortage-racked country.
The protest paralysed half the bus fleet in the city of three million people, the drivers said.
Scores of drivers parked their buses outside the transport ministry, causing havoc on the capital’s east side as they shut off one of its main arteries for nine hours.
Many blame President Nicolas Maduro for the country’s mounting economic problems.
“We’re not budging. They think they’re so important? Well, we are too,” Hugo Ocando, the spokesman, shouted from a parked bus.
Ricardo Molina, Venezuela’s transport minister, had refused to meet union leaders, blaming schedule conflicts, Ocando said before threatening that the drivers would escalate to a nationwide strike if the ministry did not give them “answers”.
The bus drivers have a simple message for the government.
”We need an adjustment of fares and we’re not asking for much, just enough to survive,” Francisco Guerrero, a protester, told Al Jazeera.
“At the moment we’re not earning enough to survive and as a result, our transportation system is grinding to a halt.”
Oil-rich Venezuela’s economy has stalled as crude prices have plunged since mid-2014.
Last year, Venezuela had the world’s highest inflation rate at 180 percent.
There is a shortage of food, medicine and electricity and has led to outbreaks of looting and riots.
In May, Maduro declared a state of emergency and says foreign powers and right-wing forces are to blame for the economic crisis.
The protesting drivers were calling on the authorities to raise the bus fare and want the increased revenue to go towards pay raises.
“Our income isn’t enough to maintain our buses or support our families,” said Ronny Blanco, a 33-year-old freelance driver.
The lack of spare parts has also paralysed around half the bus fleet, union leaders say.
Drivers who need to get their vehicles back on the road to earn money are forced to pay 200,000 bolivars on the black market – twice the government’s official price – they say.
Drivers also complain they are targets for violent crime, which has surged amid the crisis.