Thousands of elderly Venezuelans have taken to the streets of Caracas and other cities to protest against the government of Nicolas Maduro amid a worsening economic crisis.
Police blocked access to a main road in the capital and used pepper spray to try to control the crowd.
Protesters threw punches and demanded respect from police.
Venezuela is facing a shortage of many basic items, including medicines and medical equipment.
Many feel that elderly people have been particularly affected by the crisis in the health system.
At the scene: Vanessa Buschschluter, BBC Latin America editor, Merida
A university town, Merida is used to student protests. But on Friday, a steady stream of pensioners marched to the public prosecutor’s office.
One elderly man summed up their grievances: “The government is killing us in three ways. We’re dying of lack of food, we’re dying of lack of medication and they’re killing us at the protests.”
A woman with a walking stick told me she had never marched before in her life but felt it was now time to “do her bit”.
Another woman held up a sign reading: “Today I’m turning 60 and for the first time I don’t have enough for a cake.”
Florentino Montilba, 75, said he was taking to the streets because “this is the last option they’ve left us with”.
“If need be, we’ll die here on the streets,” he said.
In another development, Mr Maduro has sacked his health minister after she released official figures showing a sharp rise in child mortality and maternal deaths over the past two years.
Antonieta Caporale, a gynaecologist, had been in the post for only four months and was replaced by the Vice-Minister of Hospitals, Luis López.
“I’m here to defend my grandchildren, to defend my country,” 78-year-old Rafael Colmenares told Reuters news agency during the demonstration in Caracas.
“Respect the elderly,” many demonstrators shouted.
At the scene: Vanessa Buschschluter, BBC Latin America editor, Merida
A university town, Merida is used to student protests. But on Friday, a steady stream of pensioners marched to the public prosecutor’s office.
One elderly man summed up their grievances: “The government is killing us in three ways. We’re dying of lack of food, we’re dying of lack of medication and they’re killing us at the protests.”
Another woman held up a sign reading: “Today I’m turning 60 and for the first time I don’t have enough for a cake.”
Florentino Montilba, 75, said he was taking to the streets because “this is the last option they’ve left us with”.
“If need be, we’ll die here on the streets,” he said.
The march was diverted but it eventually reached the office of Venezuela’s ombudsman, where the protesters accused the security forces of brutal suppression.
At least 39 people have been killed since the current wave of protests began six weeks ago.
The unrest was triggered by a Supreme Court attempt to take over powers from the opposition-controlled National Assembly on 29 March.
It reversed its decision a few days later, but by then the opposition had seized the momentum.
To maintain pressure on President Maduro, opposition leaders have begun organising themed marches.
Last Friday, they urged women to take to the streets. There was a candle-lit march. And Friday’s protest was dubbed “The Grandparents March”.
The government responded with a rival march to show support to Mr Maduro, with thousands of pro-government elderly people taking to the streets of Caracas.
The opposition is calling for fresh presidential elections.
Mr Maduro says they are trying to create unrest to unsettle his democratically-elected socialist government and seize power.
Join GhanaStar.com to receive daily email alerts of breaking news in Ghana. GhanaStar.com is your source for all Ghana News. Get the latest Ghana news, breaking news, sports, politics, entertainment and more about Ghana, Africa and beyond.